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Clear skies last night, so I went Owl hunting...


r_hoskin@...
 

The short story is that my EXO2/PMC-8 is now tracking about as well as I'd hoped it would, and with a little more work, might do better yet.  :-)

I wanted to see if that 120 second unguided sub was repeatable, and it looks like it is.  I also wanted to work on my pointing and focus.  Very annoying to know you're close to the target, yet not be able to hit it.  I can get to astrometry from my back yard, so I tried their web service.  That was sufficient to help me hit the Owl nebula.  I'll get around to integrating Astrotortilla w/CdC soon, but didn't want to tackle that just yet.

The 120 sec sub was repeatable, and I tried 180 and 240 as well.  The 180 has tadpoles  (vibration, whatever else is going on), and the 240 has short streaks.  I will try this again after I've secured some vibration pads.  I also took a set of 20x60-second subs and had to toss over a third of them due to vibrations (round stars, then streaks, then back to round again...).  I think there might be a touch more I could do with my PA as well, but vibration comes before that.

The attached .zip has both long-running lights and a processed stack from the 60's set as jpgs.  I was just bumping around with DSS and StarTools trying to figure out what to do, so Owl_20180324.jpg is not ready for NASA's bragging rights page, but it's a start.

- Bob



hubbell_jerry@...
 

Hi Bob,

Very nice work, The Owl looks very nice all blue and all!  You will find that on inexpensive mounts like the EXOS 2 that there are going to be little burrs and nicks on the worm/wheel. I had it on my more expensive Skywatcher EQ6 Pro mount back when I was using an auto-guiding system 8 years ago. I typically had to throw out 20-30% of the frames due to defects (ticks and other annoying non-periodic errors). That is why early on I decided to buy the Telescope Driver Master (TDM).

That's why it is difficult to do any narrow-band imaging where you require 10-20 minute subs, although I have a customer tell me on CloudyNights (I don't think it was this forum) that he is happily getting 20 minute subs with his EXOS 2 PMC-Eight system.

Just keep at it. The imaging gods will give you just enough progress to keep you going. It's like gambling, just one more try!

Jerry Hubbell
Director Electrical Engineering
Explore Scientific, LLC.



Robert Hoskin <r_hoskin@...>
 

20 minutes!   Nice to have a goal, but how's that even possible, what with periodic error and all?  :-))

You mention burrs and nicks...what difference do you think lapping the gears would make?  Hmmm....

Having asked that... I'll be happy for now with 120 reliable and more as an available stretch.  I can do a lot of learning with that and the kit I have.  Exhausting that could get expensive.   :-)

Seriously, though, it makes the point that what you have here is considerably better than a 30 second mount. 



From: "hubbell_jerry@... [ESPMC-Eight]"
To: ESPMC-Eight@...
Sent: Saturday, March 24, 2018 7:01 PM
Subject: [ESPMC-Eight] Re: Clear skies last night, so I went Owl hunting...

 
Hi Bob,

Very nice work, The Owl looks very nice all blue and all!  You will find that on inexpensive mounts like the EXOS 2 that there are going to be little burrs and nicks on the worm/wheel. I had it on my more expensive Skywatcher EQ6 Pro mount back when I was using an auto-guiding system 8 years ago. I typically had to throw out 20-30% of the frames due to defects (ticks and other annoying non-periodic errors). That is why early on I decided to buy the Telescope Driver Master (TDM).

That's why it is difficult to do any narrow-band imaging where you require 10-20 minute subs, although I have a customer tell me on CloudyNights (I don't think it was this forum) that he is happily getting 20 minute subs with his EXOS 2 PMC-Eight system.

Just keep at it. The imaging gods will give you just enough progress to keep you going. It's like gambling, just one more try!

Jerry Hubbell
Director Electrical Engineering
Explore Scientific, LLC.





hubbell_jerry@...
 

Hi Bob,

Here is the link on CloudyNights that the guy doing 20 minute subs with his 5-inch refractor.

 
I think he is pretty happy with it. His handle is RIOT1013, I don't know if he is on this forum. My partner in our observatory purchased an EXOS 2 PMC-Eight a couple of months ago and he regularly images at 5 minutes while auto-guiding. He doesn't have to dispose of too many subs I don't think. Here is a link to the observatory Facebook page you can scroll down and look at the images he has taken with the mount using the ES ED 80 APO refractor.


I am sure that any work you can do on the gears would help the situation. You may find some things that you didn't expect to see.

Jerry Hubbell
Director Electrical Engineering
Explore Scientific, LLC.


Robert Hoskin <r_hoskin@...>
 

Thanks, Jerry!

More room to improve!  I haven't gotten to RIOT1013's careful weight biasing yet - another opportunity!  :-)

Your friend's 5 minute subs look good.  What's he using for a guide scope and guide camera?

- Bob



From: "hubbell_jerry@... [ESPMC-Eight]"
To: ESPMC-Eight@...
Sent: Saturday, March 24, 2018 9:23 PM
Subject: Re: [ESPMC-Eight] Re: Clear skies last night, so I went Owl hunting...

 
Hi Bob,

Here is the link on CloudyNights that the guy doing 20 minute subs with his 5-inch refractor.

 
I think he is pretty happy with it. His handle is RIOT1013, I don't know if he is on this forum. My partner in our observatory purchased an EXOS 2 PMC-Eight a couple of months ago and he regularly images at 5 minutes while auto-guiding. He doesn't have to dispose of too many subs I don't think. Here is a link to the observatory Facebook page you can scroll down and look at the images he has taken with the mount using the ES ED 80 APO refractor.


I am sure that any work you can do on the gears would help the situation. You may find some things that you didn't expect to see.

Jerry Hubbell
Director Electrical Engineering
Explore Scientific, LLC.



hubbell_jerry@...
 

He's using a 50 mm 210 mm FL finder scope with my QHY5 II L camera.

Jerry Hubbell
Director Electrical Engineering
Explore Scientific, LLC.