Topics

IEXOS-100 with prototype polar scope unguided images #iEXOS-100


brian skinner
 

As always, many thanks for your advise guys. I did think this was not the easiest of questions to answer definitively!!!!
The easiest first step for me I think is to down adjust the pixel size on my existing set up and see how that changes things, as Jerry suggests (many thanks Jerry), although I'm not sure how that increases the F number? As far as my mount and the existing lens set up goes I'm very happy with the tracking and so on. If adjusting the pixel size doesnt work too well I'll try a higher F number lens first before deciding on the next step.
Thanks again everybody, kind regards, Brian 

On Wed, 10 Jul 2019 21:44 Jerry Hubbell - Explore Scientific VP Engineering, <jrh@...> wrote:
On Wed, Jul 10, 2019 at 10:42 AM, Wes Mcdonald wrote:
You can get a nice little ST 80 scope for 100$.  Add $50 for the t adapter and maybe an extension tube and you will be in business at f5.  Still sort of wide.  Then add a 2x Barlow and you will be at f10 which will fill the fov for many clusters and nebula such as the Swan nebula. 
I would caution you that even though the weight limit will support the longer focal length scopes, our general advice for the iEXOS 100 mount is to not exceed 400 mm in focal length because even when guiding the residual PE will be around 2 arc-seconds which limits your plate scale to a minimum of 3-4 arc-seconds/pixel. My general advice when using any DSLR is to lower the resolution (similar to binning on an astro camera) to keep your plate scale around this level.

Modern high megapixel cameras have very small pixels, but when you select from say 16 megapixel to 4 megapixels you double the size of the pixel and you can then increase the focal length without oversampling or having a too small plate scale. This is all based on the limits of the iEXOS 100 mount mechanical performance.
 
--
Jerry Hubbell
Vice President of Engineering

Explore Scientific, LLC.
jrh at explorescientific.com

www.explorescientificusa.com
1010 S. 48th Street
Springdale, AR 72762
1-866-252-3811

Author: Scientific Astrophotography: How Amateurs Can Generate and Use Professional Imaging Data
             Remote Observatories for Amateur Astronomers: Using High-Powered Telescopes From Home


Mark Slade Remote Observatory (MSRO) IAU MPC W54 Equipment
Wilderness, VA
Mounts
: ES PMC-Eight G11 + Telescope Drive Master (TDM)
Scopes: ES 165 FPL-53 ED APO CF, ES 102 FCD100 ED APO CF
Cameras:  QHY174M-GPS + FW, QHY163C
Misc: 3-inch 0.7x Focal Reducer Field Flattener, Filters: Luminance,
Red, V-band Photometric, Diffuser, 200 lpmm Spectral Grating

Software: MaxIm DL 6, Cartes du Ciel, Astrometrica, AstroImageJ, AutoStakkert!


jrichard333 <jrichard333@hotmail.com>
 

Howdy,

 

Probably the previously owned lens was defective when you bought it?  You could always send it back to Sigma and have them inspect it.  They have a firmware update as well.

 

I have four setups for planet-imaging using an APSC-body camera:

1.       Sigma 150-600mm lens/ a combination of two teleconverters 2.8X (The Moon will fill your frame)

Focal length 1680mm/ Focal Ratio 18

 

2.       Celestron C90/ a combination of two teleconverters 2.8X/ (A Frugal-based Planet Killer J)

Focal length 3500mm/ Focal Ratio 42

 

3.       Celestron C90/ a combination of multiple teleconverters 5.6X to 11.2 X (Super-Duper Frugal Planet Killer J)

Focal length 7000mm-14000mm/ Focal Ratio 77.8 - 155.7; manually variable J

 

Super Duper Frugal Planet Killer (backend):

 

Things to note:

1.       I can’t see Polaris

2.       Red dot finder is a must for planetary and bright star imaging

3.       Current Canon/ Sigma teleconverters do not mate.  You might consider using all Vivitar or generic teleconverters.

4.       If mounting to a scope, you will have to cover the contacts of the teleconverter closet to the camera body

5.       I will only use Maksutov scopes….less headaches J.

6.       I am currently looking at picking up either the Explorer Scientific 152mm Maksutov (I love the rings) or  the Sky-Watcher 150mm Maksutov (I love the price). 

 

If you are interested in DSOs, I would go with a 150-600mm lens and pick up used teleconverters on eBAY to do planetary imaging.  Upgrade equipment as needed. 

 

I will not fulfill item 6 on my list until I have imaged Mars.  If it goes South, then I will invest in one of the scopes in item 6.

 

JR

From: MAIN@ESPMC-Eight.groups.io [mailto:MAIN@ESPMC-Eight.groups.io] On Behalf Of Wes Mcdonald
Sent: Wednesday, July 10, 2019 4:09 PM
To: MAIN@espmc-eight.groups.io
Subject: Re: [ESPMC-Eight] IEXOS-100 with prototype polar scope unguided images #iexos-100

 

Right Jerry, good advice.  The ST-80, and most other 80mm f5 scopes of course have a 400mm fl.  But the danged camera sensor can make things longer if it is a cropped sensor like a DX in Nikons.  In that case a .8 flattener/focal reducer can help.  

 

I suppose the idea of just using a good 400 mm camera prime lens is maybe the best.  I don't know.  Same as for the telescope, one would ideally want the ES 80mm APO.  All gets down to cost and where on the learning curve you are and how much you want to spend to climb up it in case you decide to bail on it.  I bought a 400mm Sigma lens for a song at a star party.  Turns out it does not focus worth beans.  Focus wheel is so soft you cannot let go of it without turning it.  Also the glass just seems poor.  Now it sits and clogs up my camera bag.  So if you go with a prime, buy a good one.

 

 

sooo, YMMV.

 

Wes.

 


--
Wes, Southport NC
PMC-8, ES ED 127, 10" LX200GPS, Astro-Tech 8" Newt, ETX-90
Polemaster, Orion ST-80 and SAG
Electrical Engineer, Retired


Wes Mcdonald
 

Right Jerry, good advice.  The ST-80, and most other 80mm f5 scopes of course have a 400mm fl.  But the danged camera sensor can make things longer if it is a cropped sensor like a DX in Nikons.  In that case a .8 flattener/focal reducer can help.  

I suppose the idea of just using a good 400 mm camera prime lens is maybe the best.  I don't know.  Same as for the telescope, one would ideally want the ES 80mm APO.  All gets down to cost and where on the learning curve you are and how much you want to spend to climb up it in case you decide to bail on it.  I bought a 400mm Sigma lens for a song at a star party.  Turns out it does not focus worth beans.  Focus wheel is so soft you cannot let go of it without turning it.  Also the glass just seems poor.  Now it sits and clogs up my camera bag.  So if you go with a prime, buy a good one.


sooo, YMMV.

Wes.


--
Wes, Southport NC
PMC-8, ES ED 127, 10" LX200GPS, Astro-Tech 8" Newt, ETX-90
Polemaster, Orion ST-80 and SAG
Electrical Engineer, Retired


Jerry Hubbell - Explore Scientific VP Engineering
 

On Wed, Jul 10, 2019 at 10:42 AM, Wes Mcdonald wrote:
You can get a nice little ST 80 scope for 100$.  Add $50 for the t adapter and maybe an extension tube and you will be in business at f5.  Still sort of wide.  Then add a 2x Barlow and you will be at f10 which will fill the fov for many clusters and nebula such as the Swan nebula. 
I would caution you that even though the weight limit will support the longer focal length scopes, our general advice for the iEXOS 100 mount is to not exceed 400 mm in focal length because even when guiding the residual PE will be around 2 arc-seconds which limits your plate scale to a minimum of 3-4 arc-seconds/pixel. My general advice when using any DSLR is to lower the resolution (similar to binning on an astro camera) to keep your plate scale around this level.

Modern high megapixel cameras have very small pixels, but when you select from say 16 megapixel to 4 megapixels you double the size of the pixel and you can then increase the focal length without oversampling or having a too small plate scale. This is all based on the limits of the iEXOS 100 mount mechanical performance.
 
--
Jerry Hubbell
Vice President of Engineering

Explore Scientific, LLC.
jrh at explorescientific.com

www.explorescientificusa.com
1010 S. 48th Street
Springdale, AR 72762
1-866-252-3811

Author: Scientific Astrophotography: How Amateurs Can Generate and Use Professional Imaging Data
             Remote Observatories for Amateur Astronomers: Using High-Powered Telescopes From Home


Mark Slade Remote Observatory (MSRO) IAU MPC W54 Equipment
Wilderness, VA
Mounts
: ES PMC-Eight G11 + Telescope Drive Master (TDM)
Scopes: ES 165 FPL-53 ED APO CF, ES 102 FCD100 ED APO CF
Cameras:  QHY174M-GPS + FW, QHY163C
Misc: 3-inch 0.7x Focal Reducer Field Flattener, Filters: Luminance,
Red, V-band Photometric, Diffuser, 200 lpmm Spectral Grating

Software: MaxIm DL 6, Cartes du Ciel, Astrometrica, AstroImageJ, AutoStakkert!


Chris Tardif
 
Edited

...I might as well round this out...

 

For comparison this one was taken with my Explore Scientific 102mm FCD-100 which is 714mm f7 scope.

 

 

Sent from Mail for Windows 10

 


From: MAIN@ESPMC-Eight.groups.io <MAIN@ESPMC-Eight.groups.io> on behalf of Chris Tardif <christardif@...>
Sent: Wednesday, July 10, 2019 12:55:51 PM
To: MAIN@ESPMC-Eight.groups.io
Subject: Re: [ESPMC-Eight] IEXOS-100 with prototype polar scope unguided images
 

There is a lot you can do with just lenses.  I started with lenses and I am still a big fan.  Lenses have the distinct advantage is that you can use them for daytime photography.  .

 

Last night I tried my 10-22 f4...clouds ambushed me so I don’t think I got any good data...

 

I bought the 400mm used and paid about $1000 CDN.  The 70-200 is less.  The shorter the focal lengths are a lot easier to set up and learn because you need to worry less about guiding and polar alignment and star alignment.

 

The left is the North America Nebula with a Canon f5.6 400mm prime and the right is a Canon 70-200 f5.6 set to 100mm.  When I get around to it I will try it at 70.

 

At this length and with that mount you have to auto-guide.

 

 

This is my pinwheel galaxy with the same 400mm lens.

 

 

Yeah

 

Sent from Mail for Windows 10

 

From: Wes Mcdonald
Sent: July 10, 2019 10:43 AM
To: MAIN@ESPMC-Eight.groups.io
Subject: Re: [ESPMC-Eight] IEXOS-100 with prototype polar scope unguided images

 

Brian

 

You need to get a long focal length lens.  My guess is it would be less expensive to buy a telescope and use it as a prime lens.  It will also have the advantage of less glass (optical loss) greater apperature (see more dim objects) and probably less coma and pincushion.  By the time you buy one of those 3 or 4 inch camera lens with 800 mm focal lengths you are talking real money...way more than the mount, way more than the exos2.

 

You can get a nice little ST 80 scope for 100$.  Add $50 for the t adapter and maybe an extension tube and you will be in business at f5.  Still sort of wide.  Then add a 2x Barlow and you will be at f10 which will fill the fov for many clusters and nebula such as the Swan nebula.  And by not using the 2x you can shoot wide field nebula and clusters such as Pleiades and the double cluster.

 

Other better telescopes also would be cheaper than the camera lens.  And realize the lens you need is sort of for special use anyhow so you probably wouldn't use it for much else anyway. Big waste of money in my view given the telescope as prime lens option.

 

I believe the iexos can easily deal with that weight.  Now understand that with an 80mm scope you will need to take longer exposures of nebula so you will likely move on to guiding.  But you will be able to shoot lots of images unguided I believe, especially with stacking and sort of high ISO.

 

Wes

 

On Wed, Jul 10, 2019 at 10:24 AM brian skinner <brianjimskinner@...> wrote:

Hi chaps, some advice from you experienced DSLR astro photographers if possible please....

I am using a Cannon EOS1300D DSLR on my IEXOS 100 mount. The camera I picked up second hand and it came with a very wide angle lens, which is great for panoramic sky shots. I would like to know the type of lens I need for more concentrated individual object shots such as star clusters, planets and deep sky objects.

Any advise would be appreciated.

 

If it helps my present lens is a fixed F3.5 lens with limited zoom capability.

 

Kind regards, Brian 

 

On Wed, 12 Jun 2019 05:02 Craig Bobchin, <cbobchin@...> wrote:

I've been testing the IEXOS with a proptype polar scope and had a chance a couple of weekends ago to take it some dark skies in Northern AZ. 

These are both single unguided 60 sec exposures. 
Pentax K-1
Pentax FA* 300mm f/4.5 @ f/4.5
ISO 3200

Rho Ophiucus area






North American Nebula (Off Center a bit)


--
Wes, Southport NC
PMC-8, ES ED 127, 10" LX200GPS, Astro-Tech 8" Newt, ETX-90
Polemaster, Orion ST-80 and SAG
Electrical Engineer, Retired

 

 


Chris Tardif
 

There is a lot you can do with just lenses.  I started with lenses and I am still a big fan.  Lenses have the distinct advantage is that you can use them for daytime photography.  .

 

Last night I tried my 10-22 f4...clouds ambushed me so I don’t think I got any good data...

 

I bought the 400mm used and paid about $1000 CDN.  The 70-200 is less.  The shorter the focal lengths are a lot easier to set up and learn because you need to worry less about guiding and polar alignment and star alignment.

 

The left is the North America Nebula with a Canon f5.6 400mm prime and the right is a Canon 70-200 f5.6 set to 100mm.  When I get around to it I will try it at 70.

 

At this length and with that mount you have to auto-guide.

 

 

This is my pinwheel galaxy with the same 400mm lens.

 

 

Yeah

 

Sent from Mail for Windows 10

 

From: Wes Mcdonald
Sent: July 10, 2019 10:43 AM
To: MAIN@ESPMC-Eight.groups.io
Subject: Re: [ESPMC-Eight] IEXOS-100 with prototype polar scope unguided images

 

Brian

 

You need to get a long focal length lens.  My guess is it would be less expensive to buy a telescope and use it as a prime lens.  It will also have the advantage of less glass (optical loss) greater apperature (see more dim objects) and probably less coma and pincushion.  By the time you buy one of those 3 or 4 inch camera lens with 800 mm focal lengths you are talking real money...way more than the mount, way more than the exos2.

 

You can get a nice little ST 80 scope for 100$.  Add $50 for the t adapter and maybe an extension tube and you will be in business at f5.  Still sort of wide.  Then add a 2x Barlow and you will be at f10 which will fill the fov for many clusters and nebula such as the Swan nebula.  And by not using the 2x you can shoot wide field nebula and clusters such as Pleiades and the double cluster.

 

Other better telescopes also would be cheaper than the camera lens.  And realize the lens you need is sort of for special use anyhow so you probably wouldn't use it for much else anyway. Big waste of money in my view given the telescope as prime lens option.

 

I believe the iexos can easily deal with that weight.  Now understand that with an 80mm scope you will need to take longer exposures of nebula so you will likely move on to guiding.  But you will be able to shoot lots of images unguided I believe, especially with stacking and sort of high ISO.

 

Wes

 

On Wed, Jul 10, 2019 at 10:24 AM brian skinner <brianjimskinner@...> wrote:

Hi chaps, some advice from you experienced DSLR astro photographers if possible please....

I am using a Cannon EOS1300D DSLR on my IEXOS 100 mount. The camera I picked up second hand and it came with a very wide angle lens, which is great for panoramic sky shots. I would like to know the type of lens I need for more concentrated individual object shots such as star clusters, planets and deep sky objects.

Any advise would be appreciated.

 

If it helps my present lens is a fixed F3.5 lens with limited zoom capability.

 

Kind regards, Brian 

 

On Wed, 12 Jun 2019 05:02 Craig Bobchin, <cbobchin@...> wrote:

I've been testing the IEXOS with a proptype polar scope and had a chance a couple of weekends ago to take it some dark skies in Northern AZ. 

These are both single unguided 60 sec exposures. 
Pentax K-1
Pentax FA* 300mm f/4.5 @ f/4.5
ISO 3200

Rho Ophiucus area






North American Nebula (Off Center a bit)


--
Wes, Southport NC
PMC-8, ES ED 127, 10" LX200GPS, Astro-Tech 8" Newt, ETX-90
Polemaster, Orion ST-80 and SAG
Electrical Engineer, Retired

 


Patrick Maher
 

Hi Brian...  Wes is correct if you want to go long focal length such as into the 400+mm range.  In that case, it is probably less expensive to get a good 420mm telescope (ie, Skywatcher Evostar ED 72mm).    However, different target/objects in the sky could be shot using inexpensive, all-manual lenses such as the Rokinon/Samyang line of lenses.  Depending on your target, you might need a 135mm...  or an 85mm.  Plugging these lenses into Stellarium and choosing objects in the sky, then choosing the camera and lens combo, will show you how your composition will be.  Using Stellarium in this way will give you a far better idea of the focal lengths necessary (which, in the end, is really the field of view that changes).  

Planets are a whole different thing.  Planets need focal length.  The longer, the better.   Forget camera lenses for this.  Actually, you can forget all relatively small telescopes too.  I'd say the minimum would be a 150mm Mak-Cass but the larger you can manage (physically and financially) the better off you will be for planets.  

Patrick
--
Explore Scientific iEXOS-100 and EXOS-2GT (non-PMC)
Explore Scientific ED 102mm Refractor


Wes Mcdonald
 

Brian

You need to get a long focal length lens.  My guess is it would be less expensive to buy a telescope and use it as a prime lens.  It will also have the advantage of less glass (optical loss) greater apperature (see more dim objects) and probably less coma and pincushion.  By the time you buy one of those 3 or 4 inch camera lens with 800 mm focal lengths you are talking real money...way more than the mount, way more than the exos2.

You can get a nice little ST 80 scope for 100$.  Add $50 for the t adapter and maybe an extension tube and you will be in business at f5.  Still sort of wide.  Then add a 2x Barlow and you will be at f10 which will fill the fov for many clusters and nebula such as the Swan nebula.  And by not using the 2x you can shoot wide field nebula and clusters such as Pleiades and the double cluster.

Other better telescopes also would be cheaper than the camera lens.  And realize the lens you need is sort of for special use anyhow so you probably wouldn't use it for much else anyway. Big waste of money in my view given the telescope as prime lens option.

I believe the iexos can easily deal with that weight.  Now understand that with an 80mm scope you will need to take longer exposures of nebula so you will likely move on to guiding.  But you will be able to shoot lots of images unguided I believe, especially with stacking and sort of high ISO.

Wes

On Wed, Jul 10, 2019 at 10:24 AM brian skinner <brianjimskinner@...> wrote:
Hi chaps, some advice from you experienced DSLR astro photographers if possible please....
I am using a Cannon EOS1300D DSLR on my IEXOS 100 mount. The camera I picked up second hand and it came with a very wide angle lens, which is great for panoramic sky shots. I would like to know the type of lens I need for more concentrated individual object shots such as star clusters, planets and deep sky objects.
Any advise would be appreciated.
 
If it helps my present lens is a fixed F3.5 lens with limited zoom capability.

Kind regards, Brian 

On Wed, 12 Jun 2019 05:02 Craig Bobchin, <cbobchin@...> wrote:
I've been testing the IEXOS with a proptype polar scope and had a chance a couple of weekends ago to take it some dark skies in Northern AZ. 

These are both single unguided 60 sec exposures. 
Pentax K-1
Pentax FA* 300mm f/4.5 @ f/4.5
ISO 3200

Rho Ophiucus area






North American Nebula (Off Center a bit)


--
Wes, Southport NC
PMC-8, ES ED 127, 10" LX200GPS, Astro-Tech 8" Newt, ETX-90
Polemaster, Orion ST-80 and SAG
Electrical Engineer, Retired


brian skinner
 

Hi chaps, some advice from you experienced DSLR astro photographers if possible please....
I am using a Cannon EOS1300D DSLR on my IEXOS 100 mount. The camera I picked up second hand and it came with a very wide angle lens, which is great for panoramic sky shots. I would like to know the type of lens I need for more concentrated individual object shots such as star clusters, planets and deep sky objects.
Any advise would be appreciated.
 
If it helps my present lens is a fixed F3.5 lens with limited zoom capability.

Kind regards, Brian 

On Wed, 12 Jun 2019 05:02 Craig Bobchin, <cbobchin@...> wrote:
I've been testing the IEXOS with a proptype polar scope and had a chance a couple of weekends ago to take it some dark skies in Northern AZ. 

These are both single unguided 60 sec exposures. 
Pentax K-1
Pentax FA* 300mm f/4.5 @ f/4.5
ISO 3200

Rho Ophiucus area






North American Nebula (Off Center a bit)


Craig Bobchin
 

In my picture of the mount in the other thread, you can kind of see it. 


Wes Mcdonald
 

Craig

Looks like your polar scope worked well!  Nice pics.

Have you shown us your scope?

Wes

--
Wes, Southport NC
PMC-8, ES ED 127, 10" LX200GPS, Astro-Tech 8" Newt, ETX-90
Polemaster, Orion ST-80 and SAG
Electrical Engineer, Retired