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Own EdgeHD 8" on alt-az mount - looking to buy HEQ5 Pro for AP!

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#1 stream41

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Posted 14 February 2020 - 02:08 PM

Hey guys, I have an EdgeHD 8" on the Evolution alt-az mount, and I'm loving it for visual stuff. However, I've wanted to get into some AP, and with the f/10 ratio at 2000mm I can't get very long exposures with the alt-az mount. So I've thought about an HEQ5 Pro. Ideally I'd like the HEQ5 Pro to replace the alt-az mount, and I could use it for both visual and AP. The idea of replacing my current mount with a GEM has a much higher "wife acceptance factor" than buying a refractor AND a mount while keeping the full old setup too.

 

So I know the f/10 on the SCT is gonna be tough for AP, but I'm up for the challenge. I'll be using a Canon 6D Mark II, which has excellent high ISO performance. Can't I just jack the ISO up a little higher (3200 or 6400) to compensate for the slow f/10 ratio? Then I'm not also buying a $300 focal reducer or a $1000 Hyperstar, etc. I'm primarily interested in DSO targets.

 

I love using Starsense to align, but I'm a fast learner and polar alignment and star alignment on the GEM shouldn't be too tough to learn. After that, it will function almost just like the Evolution mount right? Similar GoTo systems, but with more accurate tracking on the GEM.

 

So two main questions:

 

1) Could an HEQ5 Pro replace my alt-az mount for both visual and a reasonable amount of AP?

2) Can my 6D-II's excellent higher ISO compensate for the f/10 ratio of the SCT? Or will I just need to suck it up and do auto guiding or shorter exposures?

 

‚ÄčEdit: So here's a better question. Will switching to an HEQ5 Pro (or EQ6-R) give me the same visual performance as the Evolution alt-az, while still giving me some improvement for AP? Then I can invest in a focal reducer or Autoguider setup later.

 

More Edits: So I've halfway talked myself into a ProED 80mm APO for the AP stuff, but I'd like to also use the 8 EdgeHD on the GEM for small DSO's. So you guys think I need to be on a EQ6-R? I weighed my EdgeHD/DSLR setup, and it was 16 lbs, but that's without any auto guiding stuff I might add.


Edited by stream41, 15 February 2020 - 12:37 AM.


#2 Madratter

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Posted 14 February 2020 - 02:19 PM

1) For visual yes. For astrophotography, I wouldn't recommend it. I like the EQ5s and I frequently recommend them. But there capacity is just 30 lbs. That is visual capacity. For imaging, divide that in half to have a stable platform. The 8" Edge alone is 14 lbs. Once you add in things like cameras, dew prevention, guiding, etc., you are going to go way over.

 

2) No. You can't manufacture information out of thin air by simply turning up the ISO. That's like trying to hear a radio program full of static by turning up the volume.


Edited by Madratter, 14 February 2020 - 03:15 PM.


#3 vancoz

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Posted 14 February 2020 - 02:37 PM

My Orion Sirius (HEQ5 analog) performs good with C8+OAG or 60mm scope + pretty heavy camera and reducer/corrector + lens shade + heaters + asiair. Total weight is ~18-20pounds. But it performs good in calm good weather, in case of wind - doing AP almost impossible.  

My mount has standard tripod with about 30 pounds attached to it to increase stability, but I've seen reviews where folks was using it really close to full capacity mounted on pier.

Also HEQ5 can have pretty big backlash and it could be an issue for guiding on 2000mm focal length, of course you can upgrade your mount to belt (what I'm going to do next wink.gif ).

And I would recommend guiding setup in case if you would like to do DSO AP on long focal length, btw I was trying my C8 with no guiding and reducer at all, and if you do some bright objects - like ring nebula - and you can be in range 20-40sec exposure I think you can get good results too if your polar alignment is good. For me mine issue was coma effect so I had to get good reducer/corrector for AP.   


Edited by vancoz, 14 February 2020 - 02:43 PM.


#4 JohnKulczycki

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Posted 14 February 2020 - 02:59 PM

Can you get a wedge for your Evolution mount? It wouldn't be perfect but it would get you going for a while in Astrophotography.



#5 AstroPics

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Posted 14 February 2020 - 03:10 PM

I second the overall response from above about the EQ5s. You will have just a bit too much weight for AP. You could make it work sometimes but may be frustrated by variations in performance.

 

I'd suggest a Sky Watcher EQ6-R. It is roughly $500 more than the EQ5 but a solid investment (with a max payload of 44 pounds).

 

Also, I'd recommend investing in the focal reducer for the EdgeHD. Bringing the scope down to f/7 will be a major help for AP.


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#6 SilverLitz

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Posted 14 February 2020 - 03:53 PM

I would expect a EQ6-R would be the minimum for Edge800.

 

Looking at ISO info on the 6Dmk2, I would expect that you could go to ISO 3200, as that is about where it is ISO invariant.  This makes sense at ISO 1600 is the sweet spot for my APS-C 7Dmk2, and I would expect the full-frame sensor to be about a stop better.

 

I would expect that you will want the focal reducer, as 1422mm FL (87'x58' FoV) fits more targets than native 2032mm (60'x40' FoV).  The exception would be small galaxies and planetary nebulas.  But at 2032mm, you will be limited by your seeing conditions and your mount's ability to track such fine image scales.  The focal reducer will be an even bigger advantage if you ever go to cooled astrocams, as the FoV and image scale issues will be more significant.



#7 17.5Dob

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Posted 14 February 2020 - 09:48 PM

I wouldn't put an 8" Edge on anything less than an EQ6


Edited by 17.5Dob, 14 February 2020 - 09:49 PM.


#8 stream41

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Posted 15 February 2020 - 12:44 AM

Okay, halfway talked myself into an EQ6-R and a SW ProED 80mm APO. So I'll be using the 6D-II on that ProED. I need the SW 0.85x focal reducer, and then an M48 t-ring, and then the 6D-II, right? After that I'm rocking and rolling!

 

So with that in mind, here's the million dollar question. I'll probably be using the ProED 80 for my AP stuff at first, but how will the EdgeHD do on that EQ6-R for just visual stuff? I know I'll lose WiFi, Star Sense, etc - but what other implications am I missing by going from Alt/Az to GEM for visual with the EdgeHD? You can see where I'm going - I'd like to sell the Evolution mount/tripod/StarSense to help fund all the new gear, and just run both the ProED 80 and EdgeHD 8 off the new GEM.



#9 Stelios

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Posted 15 February 2020 - 03:20 AM

Okay, halfway talked myself into an EQ6-R and a SW ProED 80mm APO. So I'll be using the 6D-II on that ProED. I need the SW 0.85x focal reducer, and then an M48 t-ring, and then the 6D-II, right? After that I'm rocking and rolling!

 

So with that in mind, here's the million dollar question. I'll probably be using the ProED 80 for my AP stuff at first, but how will the EdgeHD do on that EQ6-R for just visual stuff? I know I'll lose WiFi, Star Sense, etc - but what other implications am I missing by going from Alt/Az to GEM for visual with the EdgeHD? You can see where I'm going - I'd like to sell the Evolution mount/tripod/StarSense to help fund all the new gear, and just run both the ProED 80 and EdgeHD 8 off the new GEM.

Once you get an EQ6R-Pro, you should consider the $300 reducer before you give up on the EdgeHD 800 which is a *wonderful* AP scope. Imaging at 1421mm and F/7 is SO much better than imaging at 2030mm and F/10. Half the exposure time. Much easier guiding. Wider FOV. Same detail. (I'm not saying to *not* get the 80mm--the two scopes beautifully complement each other). 

 

You are missing nothing by going from Alt-Az to GEM. Plate-solving will land all your targets for AP. For visual you can polar align, star align manually and use your GoTo as always (via SkySafari as well). There's WiFi adapters for Synscan (the EQ6R-Pro's OS). (see also this).


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#10 stream41

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Posted 15 February 2020 - 09:30 AM

Once you get an EQ6R-Pro, you should consider the $300 reducer before you give up on the EdgeHD 800 which is a *wonderful* AP scope. Imaging at 1421mm and F/7 is SO much better than imaging at 2030mm and F/10. Half the exposure time. Much easier guiding. Wider FOV. Same detail. (I'm not saying to *not* get the 80mm--the two scopes beautifully complement each other). 

 

You are missing nothing by going from Alt-Az to GEM. Plate-solving will land all your targets for AP. For visual you can polar align, star align manually and use your GoTo as always (via SkySafari as well). There's WiFi adapters for Synscan (the EQ6R-Pro's OS). (see also this).

It is a great scope, and I'm definitely not giving up on it! I'm just getting the hint that the faster ProED 80mm will be much easier to learn AP, but the EdgeHD 8 can still be a fine visual scope until I can throw a reducer on there once I beef up my AP chops.

 

By the way, do I need the flattener/reducer for the 80mm? Is it a back focus issue? I know it flattens the edges and makes the scope a little faster, but it's already pretty fast to begin with, and it would be nice to save ~$300 if I can just throw the DSLR directly onto the scope with a M48 adapter. At this point a few oval stars on the edges of the frame aren't worth $300 to me, at least not at first when I'm spending all this other money. Or, do I have to have the reducer to make the M48 adapter/DSLR work?



#11 bobzeq25

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Posted 15 February 2020 - 10:38 AM

Hey guys, I have an EdgeHD 8" on the Evolution alt-az mount, and I'm loving it for visual stuff. However, I've wanted to get into some AP, and with the f/10 ratio at 2000mm I can't get very long exposures with the alt-az mount. So I've thought about an HEQ5 Pro. Ideally I'd like the HEQ5 Pro to replace the alt-az mount, and I could use it for both visual and AP. The idea of replacing my current mount with a GEM has a much higher "wife acceptance factor" than buying a refractor AND a mount while keeping the full old setup too.

 

So I know the f/10 on the SCT is gonna be tough for AP, but I'm up for the challenge. I'll be using a Canon 6D Mark II, which has excellent high ISO performance. Can't I just jack the ISO up a little higher (3200 or 6400) to compensate for the slow f/10 ratio? Then I'm not also buying a $300 focal reducer or a $1000 Hyperstar, etc. I'm primarily interested in DSO targets.

 

I love using Starsense to align, but I'm a fast learner and polar alignment and star alignment on the GEM shouldn't be too tough to learn. After that, it will function almost just like the Evolution mount right? Similar GoTo systems, but with more accurate tracking on the GEM.

 

So two main questions:

 

1) Could an HEQ5 Pro replace my alt-az mount for both visual and a reasonable amount of AP?

2) Can my 6D-II's excellent higher ISO compensate for the f/10 ratio of the SCT? Or will I just need to suck it up and do auto guiding or shorter exposures?

 

‚ÄčEdit: So here's a better question. Will switching to an HEQ5 Pro (or EQ6-R) give me the same visual performance as the Evolution alt-az, while still giving me some improvement for AP? Then I can invest in a focal reducer or Autoguider setup later.

 

More Edits: So I've halfway talked myself into a ProED 80mm APO for the AP stuff, but I'd like to also use the 8 EdgeHD on the GEM for small DSO's. So you guys think I need to be on a EQ6-R? I weighed my EdgeHD/DSLR setup, and it was 16 lbs, but that's without any auto guiding stuff I might add.

Here's what you're missing.  There's a _big_ difference between learning imaging and doing imaging.  Even on a good mount, the SCT is a terrible choice to learn on.  You'd learn faster/better/cheaper if you start with a small (shorter/lighter/faster) scope.  If your goal is to image small galaxies with a big scope, you'll reach it faster/better/cheaper, if you start with a small scope and big targets.

 

It's not a question of "challenge".  It's a matter of using the right tool for the job.  Starting out with an SCT is like trying to learn building fine furniture while banging in nails with a crescent wrench.  You'll learn much better if you use a hammer.  Two illustrative quotes, I have many more.

 

A talented beginner, looking back on his first year.

 

"First and foremost is listen to the folks who have been there. The philosophy of 80MM APO and good $1500-2000 mount is great advice for beginners. Sure you can possibly <learn to> image as a beginner with something that is larger or that you may have but holy cow its hard enough with something small."

 

Dr. Craig Stark, noted astrophotographer, who wrote the PhD program you'll be using for autoguiding, on the best starter scope.  It's not only what he says, it's how he says it.  He's been here before, and he's talking straight to you.

 

"As light as possible.

 

Seriously.

 

No, seriously".

 

He knows that means a small refractor.  <smile>

 

"I'm just getting the hint that the faster ProED 80mm will be much easier to learn AP, but the EdgeHD 8 can still be a fine visual scope until I can throw a reducer on there once I beef up my AP chops."

 

Bingo.  I'm not big on hints <smile>, this is so unintuitive to beginners, I get out the hammer.  <grin>

 

The reducer makes it even easier.  The flattener makes your stars at the corners look better, but has little impact on learning.

 

This book will be a big help, there's far more to learn than you can get from short posts here.

 

https://www.amazon.c...d/dp/0999470906

 

You can get images with the SCT, stacking frames is very powerful.  You'll reach your full potential as an astrophotographer if you start small.


Edited by bobzeq25, 15 February 2020 - 10:43 AM.


#12 Kendahl

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Posted 15 February 2020 - 11:21 AM

The equipment you have now will work for solar, lunar and planetary photography. (You would need a filter for solar.) An altitude-azimuth mount isn't a hindrance because the targets are bright enough to permit fast shutter speeds even with a slow optical tube. You need a long focal length for planets. An alt-az mount does a poor job on DSOs because of field rotation during the necessarily much longer exposure durations.

 

The HEQ5 is a good mount with a long track record. However, it is limited by its 30 pound payload capacity. That's for visual observing. Drop it to 15 to 20 pounds for astrophotography. AP is that demanding of stability. An EQ6 gives you more room for heavier optical equipment. Note that there are mounts in the same payload range from Celestron and iOptron.

 

Tracking with sufficient accuracy gets much more difficult as focal length increases. That's the principal reason why an optical tube with a focal length well under 1,000 mm is recommended for beginners. A refractor has the advantage that it doesn't require routine collimation. A fast focal ratio cuts down on subexposure duration. Triplet ED refractors have the least chromatic aberration.

 

You will need an autoguider. It can be a separate optical tube piggybacked on the main one or it can be an off axis guider on the main tube. Piggyback is easier but off axis works better with Schmidt-Cassegrains.

 

Your EdgeHD has a focal ratio of 10. That's very slow for DSO photography. A focal length reducer, specific to the 8" model, will reduce that to f/7. It also widens the field of view which makes tracking easier. Even with the reducer, the effective focal length is still pretty long.

 

What do you have for camera lenses? A good starting point would be to put a camera and lens on an equatorial mount and take wide field photos. You might have to jack up ISO in order to keep subexposure durations short enough to prevent star trails. You can learn image processing without having to fight difficult equipment issues.




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