First Light! Edge HD 8 Amateur Hour - M63

[eshy76]

Hi everyone,

I've been into astrophotography for a couple of years now and I've largely relied on one scope - the William Optics ZS73 430mm refractor...an amazing piece of kit - I'm not sure I could've picked a better first ota to get into this hobby. I've been honing my skills and have become pretty decent, unafraid to aim my trusted frac at even tiny targets, knowing we would make a decent fist of it.

So, I've only gone and got aperture fever and bought a blimming Edge HD 8! Back down the learning curve I go. For once, the new kit was accompanied by clear skies, so no time to carefully build the rig...get the thing on the mount and get outside! Ouch...clear night one was spent trying to cobble together a makeshift velcroed rig from my Z73 setup (the top dovetail was in the post), clear night 2 went utterly failing to resolve a guide star with the ASI120 and ZWO OAG (the ASI290 is in the post...eventually will move onto a Celestron OAG). 

Two clear nights without an image was too much to bear, so on night three, I just had to get something, anything, so stopped trying to do the right things - mount a 30mm miniguide scope (all I had!) to guide 2032mm focal length? Check. Use a barbell weight to desperately try to balance the OTA? Check. Leave all the wires hanging when imaging at F10 (the reducer is in the post)? Expect my CEM25P (no upgrade for a while) to cope with all this weight? Check.

Anyway, I present M63 - sorry to break the run of all the stunners in galaxy season so far, but I am so happy to get any sort of image under my belt with a bunch of new kit and at a focal length way in advance of anything I've ever tried before. Misshapen stars, botched focus and lack of integration time, sure....but one of my most satisfying shots in a weird kind of way! Something to build on!

Approx 3 hours of integration time.

Thanks for looking and sorry for the long post!


 

[eshy76]

And here's the makeshift rig! My poor mount!

[lux eterna]

That is a good start, and from now on everything will be easier as you develop the setup and your routines. Perfect timing as you will be well prepared when autumn comes (I think I would have started with the cabling 😉 ).

Ragnar

 

[eshy76]

19 minutes ago, lux eterna said:

That is a good start, and from now on everything will be easier as you develop the setup and your routines. Perfect timing as you will be well prepared when autumn comes (I think I would have started with the cabling 😉 ).

Ragnar

 

Thank you! It's been painful at times before getting the first image, but I've learnt an enormous amount...both mechanically and software wise, PHD2 settings, getting platesolving to work at this scale, etc. As you say, I can definitely see where the improvements will come from!

[geeklee]

Love the ad-hoc rig and perseverance on getting it going. Best bits are the barbell and little guide scope 🙂 👍 Great you got some good output!

What a beast that is on the CEM25 😮

Great write up. 

[rl]

I'm impressed with that image given that you're using a small guide scope with a long focus OTA. I've never tried a separate guidescope at that sort of focal length...the advice is always to use an OAG. 

Well done.

[eshy76]

2 hours ago, geeklee said:

Love the ad-hoc rig and perseverance on getting it going. Best bits are the barbell and little guide scope 🙂 👍 Great you got some good output!

What a beast that is on the CEM25 😮

Great write up. 

Thank you!

[eshy76]

2 hours ago, rl said:

I'm impressed with that image given that you're using a small guide scope with a long focus OTA. I've never tried a separate guidescope at that sort of focal length...the advice is always to use an OAG. 

Well done.

Thank you! I was just happy to see any stars at all in PHD2 after a night moving the ASI120 up and down on the OAG stalk to no avail!

The guiding seemed incredible on the smaller scope too - was getting something like 0.2-0.3 pixels...flat blue and red lines...like the best ever! But one of the things I learned in the last few days, is what the numbers in the brackets in PHD2 means...i.e. arc seconds error...and why that is more important, so the smaller guidescope magnifies the error in arcseconds, which leads to bigger pixel error on the imaging scope at such a long focal length (if I've understood correctly).

I DO think it is doable, though, as my mount has always had severe DEC backlash and I was pushing the payload too...actually when I move back to using my widefield refractor, I might think about using the miniscope for guiding, as PHD2 just seemed happier, you know?

It is fun to challenge the conventional wisdom sometimes, as much as it cool to learn from more experienced imagers!

[geeklee]

39 minutes ago, eshy76 said:

like the best ever! But one of the things I learned in the last few days, is what the numbers in the brackets in PHD2 means...i.e. arc seconds error.

Yeah, that looks like the QHY mini guide scope - so 130mm focal length.  Not sure what pixel size that camera has but if it similar to the mini version then 3.75 (?).  The image scale for that is (206 * 3.75) / 130 = ~5.96 arc sec / per pixel ("PP).  So 0.2 pixels of guide error is 5.94 * 0/2 = ~1.19 arc sec (").  Plug the imaging camera pixel size and Edge HD 8 focal  length into calculation earlier and you'll get it's imaging scale to compare against the error.  One of the reasons your OAG is the way forward for the Edge HD 8 I guess!  Agree for the ZS73, more likely to be happier at that scale and worth trying.

39 minutes ago, eshy76 said:

actually when I move back to using my widefield refractor, I might think about using the miniscope for guiding, as PHD2 just seemed happier, you know?

Here was me starting to picture the ZS73 on top of the Edge HD 8 as a guide scope 😅 I think the CEM25 might fail entirely with that scenario!

Edited April 25, 2020 by geeklee

[eshy76]

32 minutes ago, geeklee said:

Yeah, that looks like the QHY mini guide scope - so 130mm focal length.  Not sure what pixel size that camera has but if it similar to the mini version then 3.75 (?).  The image scale for that is (206 * 3.75) / 130 = ~5.96 arc sec / per pixel ("PP).  So 0.2 pixels of guide error is 5.94 * 0/2 = ~1.19 arc sec (").  Plug the imaging camera pixel size and Edge HD 8 focal  length into calculation earlier and you'll get it's imaging scale to compare against the error.  One of the reasons your OAG is the way forward for the Edge HD 8 I guess!  Agree for the ZS73, more likely to be happier at that scale and worth trying.

Here was me starting to picture the ZS73 on top of the Edge HD 8 as a guide scope 😅 I think the CEM25 might fail entirely with that scenario!

My CEM25P would keel over at that point!

[Astrocecco]

Hello Eshan,

great post and congratulations for the perseverance. I've got the same mount and am using  it with a Stellarvue 102 on top, but I've been drooling over an Edge HD8" for months, now. Seeing that you were able to mount it on your CEM25P is a big encouragement, but the question is: considering the Max payload of 27 pounds and the OTA weighing 13-14 pounds itself (it still sounds promising as far as holding it properly even for astrophotography), do you recommend going for it or one should rather upgrade to a bigger mount? I'd be using it for astrophotography but at f/7 f=1,400mm rather than f/10 f=2,000mm...

Thank you beforehand for your answers and congratulations on your Astrobin page, really good pictures!

Andrew

[eshy76]

On 16/10/2020 at 16:02, Astrocecco said:

Hello Eshan,

great post and congratulations for the perseverance. I've got the same mount and am using  it with a Stellarvue 102 on top, but I've been drooling over an Edge HD8" for months, now. Seeing that you were able to mount it on your CEM25P is a big encouragement, but the question is: considering the Max payload of 27 pounds and the OTA weighing 13-14 pounds itself (it still sounds promising as far as holding it properly even for astrophotography), do you recommend going for it or one should rather upgrade to a bigger mount? I'd be using it for astrophotography but at f/7 f=1,400mm rather than f/10 f=2,000mm...

Thank you beforehand for your answers and congratulations on your Astrobin page, really good pictures!

Andrew

Hi there - sorry to take so long to get back to you. Moving from a refractor to the Edge has been a massive challenge - lots of new things to learn. Very fussy with the reducer and spacing. Needed a more sensitive guide cam when using an OAG at 2032mm! All of the above! 

My mount has had DEC issues for a while, but if it didn't I think I could get it to work on the CEM25P. However, a new mount is my next priority, probably something like the CEM70 to get the most out of the scope. With the Edge HD on the CEM25P, you would need some extra counterweights and as long as your mount is mechnically fine, it should work. This focal length does amplify errors in your imaging train or any mount issues though, so if you have any backlash like mine does, I would probably upgrade the mount.

I hope that helps!
 

[eshy76]

On 16/10/2020 at 16:02, Astrocecco said:

Hello Eshan,

great post and congratulations for the perseverance. I've got the same mount and am using  it with a Stellarvue 102 on top, but I've been drooling over an Edge HD8" for months, now. Seeing that you were able to mount it on your CEM25P is a big encouragement, but the question is: considering the Max payload of 27 pounds and the OTA weighing 13-14 pounds itself (it still sounds promising as far as holding it properly even for astrophotography), do you recommend going for it or one should rather upgrade to a bigger mount? I'd be using it for astrophotography but at f/7 f=1,400mm rather than f/10 f=2,000mm...

Thank you beforehand for your answers and congratulations on your Astrobin page, really good pictures!

Andrew

Hi Andrew, 

Just as a follow up to show the improvement on the CEM25P Edge combo, here was my second attempt at a galaxy, M81...with further refinement and improvements to the overall rig, this scope can definitely work on the CEM25P...you've got to want it though!

Thanks for the kind words!