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

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.





Sent from Mail for Windows 10


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




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.




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



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