Help me spend some money at FLO

[Chris]

24 minutes ago, pete_l said:

The easiest "improvements" are to reduce the exposure time such that stars don't trail. Once their light starts to spread across multiple pixels you get no further benefit. And with shorter exposures, take more of them. After that it's down to processing.

There is a reason that the Ford Transit¹ of imaging is an HEQ5 + ED80 and DSLR. It is not fancy and produces results. It is also about at the bottom end, price-wise for entry into deep sky imaging.

[1] a van that just about every van driver has used at some point.

I agree Pete, for the above quick snap I should have really stuck to the 500 rule, so using a 28mm lens on a 2x crop M43 sensor I should have been around 10 seconds. However, when I tried 10 seconds you couldn't really make out the galaxy, so I tried up to 30 seconds but found 15-20 seconds to be the best compromise. Keep in mind the above is a severe crop so the smearing wasn't as apparent before I 'zoomed' in

Absolutely, if you're purely into DSO imaging the ED80 on an HEQ5 is the starting point for very good DSO images upwards. FLO even sell this as a bundle for £1275. I don't however believe this setup is the starting point for any type of DSO imaging, or the setup for anyone with varied interests in astronomy. I know my above images aren't amazing by any stretch of the imagination (Look at my old processing for a start!) but they were taken with really cheap kit! For example the M27 was a 150p and a motor driven EQ3 or EQ5 (I've owned both but can't remember which) plus self modded Canon 350D. I didn't even have a coma corrector! but I still imaged M27  

[happy-kat]

For me if you've already owned some of the gear mentioned it didn't tick your boxes otherwise you would likely still have it in your shed.

[Chris]

32 minutes ago, Skyline said:

You've had it before, why not have it again:

sw130pds with something like a eq5/heq5 pro mount. good for handling, visual and imaging also does not break the bank account. If you want I can print a focus mask out for you - foc.

Nadeem.

Hey Nadeem Actually before I started this thread the 130pds or 150p were in my head for their performance per pound. I even had the 200p EQ5 with motor drive kit in my head thinking it would great for Lunar/planetary and visual, but then realised maybe the focal length would be too much to get reliable 60 second subs for DSO's even.

I'm checking out YT vids on the SW AZ-GTI but not sure after my bad experience of tablet controlled scopes when reviewing the Astro FI 90. That scope drove me nuts lol 

I still have the mask from my old 130pds, but very much appreciate the offer.   

[Chris]

Thinking about it the 150p or 200p EQ5 would work if I purely piggy backed my camera with lenses for DSO imaging. I have an old 200mm M42 fit lens somewhere. 

[Chris]

15 minutes ago, happy-kat said:

For me if you've already owned some of the gear mentioned it didn't tick your boxes otherwise you would likely still have it in your shed.

Nooo honestly, I've sold so much kit in the past either because I was stupid and the grass looked greener, or I simply needed the money. I had 3K of kit until the beginning of this year, but very much needed to sell it all to buy the house we will stay in and raise our kids. We had to buy a new boiler in the first week so it was a good job I sold the shirt off my back! lol. 

Trust me I've owned 30+ scopes and have regretted selling at least 10 of these. But I tend to use astro kit as money sometimes, hence they come and go. 

[happy-kat]

I see 🙂

If going eq5 with 200mm telescope don't piggy back that with your camera and 200mm 42 lens as you lose the benefit of the light lens straight away as you are still placing the heavy wind sail of the 200mm telescope on the mount. (Lol confusing with your 200mm aperture versus 200mm focal length)

[Chris]

3 minutes ago, happy-kat said:

I see 🙂

If going eq5 with 200mm telescope don't piggy back that with your camera and 200mm 42 lens as you lose the benefit of the light lens straight away as you are still placing the heavy wind sail of the 200mm telescope on the mount. (Lol confusing with your 200mm aperture versus 200mm focal length)

Oh very good point! I'd totally forgot what I pain the wind was! It's a real shame I can't afford An ED100 f7 on an EQ5 that would have been perfect.

I guess I could either get the 130pds, to avoid the wind sail, or get the 200p for planetary, lunar, and observing, then just use the mount with the camera and 200mm lens for deep sky imaging?

[Skyline]

A 100ED is a nice alternative to a 200mm newt, easy to handle, good for visual and some dabbling imaging with brighter dso's also if you want planetary and lunar imaging but without the weight of a newt and also better handling. 

When the moon was at its gibbous phase earlier this month I was observing the moon with my 100ED. Not a hint of false colour.

It's a good compromise over a 200m newt, grab and go.

Nadeem

[Chris]

26 minutes ago, Skyline said:

A 100ED is a nice alternative to a 200mm newt, easy to handle, good for visual and some dabbling imaging with brighter dso's also if you want planetary and lunar imaging but without the weight of a newt and also better handling. 

When the moon was at its gibbous phase earlier this month I was observing the moon with my 100ED. Not a hint of false colour.

It's a good compromise over a 200m newt, grab and go.

Nadeem

It's just the money mate, else I'd jump at an ED100, especially as a self confessed refractor man. I just can't escape the fact that a Newt is over half a grand cheaper. 

[RobertI]

8 hours ago, Lockie said:

It's just the money mate, else I'd jump at an ED100, especially as a self confessed refractor man. I just can't escape the fact that a Newt is over half a grand cheaper. 

There’s a 100ED Equinox on ABS for £595 (ONO). 😈

[Chris]

23 minutes ago, RobertI said:

There’s a 100ED Equinox on ABS for £595 (ONO). 😈

lol Don't...just don't  

I could probably afford an 100mm achro lol 

I might have a look around today and see if I can find anything else to sell to increase the budget!

Edited December 19, 2019 by Lockie

[Skyline]

10 hours ago, Lockie said:

It's just the money mate, else I'd jump at an ED100, especially as a self confessed refractor man. I just can't escape the fact that a Newt is over half a grand cheaper. 

Then I would go for something like a 130PDS, slightly bigger aperture without CA and invest more on the mount.

Nadeem.

[carastro]

Personally I'd go for a Skywatcher 130PDS (£180) and a 2nd hand HEQ5, this will cover most bases.  Planets won't be huge, but with a Barlow I think you will manage.   You'll never manage satisfactory DSO imaging with an alt-Az mount. 

Oh, you said you would buy from FLO, so second hand won't cut it.  New HEQ5 and SW130PDS is about £929 without any extras such as a coma corrector.  

the Sky-Watcher EQ5 PRO Go-To is cheaper @ £569 and has GOTO and guide port so may well suffice.  total spend £748.  But you will need to add a guide camera to that.  

Carole 

Edited December 19, 2019 by carastro

[Chris]

41 minutes ago, Skyline said:

Then I would go for something like a 130PDS, slightly bigger aperture without CA and invest more on the mount.

Nadeem.

 

34 minutes ago, carastro said:

Personally I'd go for a Skywatcher 130PDS (£180) and a 2nd hand HEQ5, this will cover most bases.  Planets won't be huge, but with a Barlow I think you will manage.   You'll never manage satisfactory DSO imaging with an alt-Az mount. 

Oh, you said you would buy from FLO, so second hand won't cut it.  New HEQ5 and SW130PDS is about £929 without any extras such as a coma corrector.  

the Sky-Watcher EQ5 PRO Go-To is cheaper @ £569 and has GOTO and guide port so may well suffice.  total spend £748.  But you will need to add a guide camera to that.  

Carole 

Hi both, with regards to the DSO imaging side of things there are two sides to me:

1) the sugar coated side which thinks I would regularly get a big enough gap in the weather and my schedule to setup a mobile goto rig with guiding, laptop, plus the fine tweaks of PA needed for longer focal lengths etc.

Then there's person 2) Slightly depressingly realistic individual that thinks using my 200mm lens camera combo on a motor driven mount is the most I'd realistically get do both regularly and with any great success. 

Person 1 would with my tight budget probably buy FLO's 130pds EQ3 Pro combo for £628. Or try and scrape more money together for an EQ5 Pro thus waiting until early next year. 

Person 2 would probably buy an EQ5 with motor drive, and use it for DSO imaging with a camera and lens. Then a separate OTA for visual, planetary, and lunar such as a 150pds, or even a 200p or 127Mak or whatever. 

 

 

[vlaiv]

1 hour ago, Lockie said:

 

Hi both, with regards to the DSO imaging side of things there are two sides to me:

1) the sugar coated side which thinks I would regularly get a big enough gap in the weather and my schedule to setup a mobile goto rig with guiding, laptop, plus the fine tweaks of PA needed for longer focal lengths etc.

Then there's person 2) Slightly depressingly realistic individual that thinks using my 200mm lens camera combo on a motor driven mount is the most I'd realistically get do both regularly and with any great success. 

Person 1 would with my tight budget probably buy FLO's 130pds EQ3 Pro combo for £628. Or try and scrape more money together for an EQ5 Pro thus waiting until early next year. 

Person 2 would probably buy an EQ5 with motor drive, and use it for DSO imaging with a camera and lens. Then a separate OTA for visual, planetary, and lunar such as a 150pds, or even a 200p or 127Mak or whatever. 

 

 

Maybe it would help to stop thinking in terms of focal length and start thinking in sampling rate when you want to think about periodic error for example or polar alignment error and exposure length.

Let's suppose that you have drift due to poor PA or RA periodic error of something like 0.1"/s. How much can you expose before this trailing becomes 1 pixel long? Well - that depends on how "big" your pixels are in relation to focal length (and not focal length alone).

Suppose that with 200mm lens you sample at something like 4.5"/px. In this case you can have exposure length of 45 seconds and still keep trailing less than one pixels - virtually undetectable. With 750mm focal length scope you will sample at 1.18"/px, and in this case exposure length will be something like 11.8 seconds.

But what happens if you bin data from 750mm scope? If you bin x2 - then you are no longer at 1.18" but rather at 2.36"/px, and exposure length now can go as much as 23.6s. If you bin x3 then you have 3.54"/px and possible exposure goes to 35.4s. Bin by x4 and you will be matching your 200mm lens (with much larger aperture) at 4.73"/px and 47.3s exposure without any visible trailing.

Only drawback is smaller FOV, but if you want wider field - you can switch to lens or even if you don't have lens - you can still use scope and do mosaics. That will be almost as equally fast as using F/5 lens (provided that scope is 150PDS - which is F/5) with small focal length.

I've written this to say that Person 2 can use larger OTA for DSO imaging as well if there is solid understanding of how things work, what are limitations and how to process your data to get there. I would however keep things simple on EQ5 class mount and go with 6" aperture max (8" is just too much). Maybe even consider F/6 newtonian if coma corrector is too much for the budget.

[Chris]

1 hour ago, vlaiv said:

Maybe it would help to stop thinking in terms of focal length and start thinking in sampling rate when you want to think about periodic error for example or polar alignment error and exposure length.

Let's suppose that you have drift due to poor PA or RA periodic error of something like 0.1"/s. How much can you expose before this trailing becomes 1 pixel long? Well - that depends on how "big" your pixels are in relation to focal length (and not focal length alone).

Suppose that with 200mm lens you sample at something like 4.5"/px. In this case you can have exposure length of 45 seconds and still keep trailing less than one pixels - virtually undetectable. With 750mm focal length scope you will sample at 1.18"/px, and in this case exposure length will be something like 11.8 seconds.

But what happens if you bin data from 750mm scope? If you bin x2 - then you are no longer at 1.18" but rather at 2.36"/px, and exposure length now can go as much as 23.6s. If you bin x3 then you have 3.54"/px and possible exposure goes to 35.4s. Bin by x4 and you will be matching your 200mm lens (with much larger aperture) at 4.73"/px and 47.3s exposure without any visible trailing.

Only drawback is smaller FOV, but if you want wider field - you can switch to lens or even if you don't have lens - you can still use scope and do mosaics. That will be almost as equally fast as using F/5 lens (provided that scope is 150PDS - which is F/5) with small focal length.

I've written this to say that Person 2 can use larger OTA for DSO imaging as well if there is solid understanding of how things work, what are limitations and how to process your data to get there. I would however keep things simple on EQ5 class mount and go with 6" aperture max (8" is just too much). Maybe even consider F/6 newtonian if coma corrector is too much for the budget.

You're right. It's certainly equally about how fine the camera pixels are as well as the focal length. The combination of which giving the sample rate. My Fuji mirrorless has a weak IR filter so I'll probably use that over my Pany GH3. The Fuji also has the larger APS-C sensor at 24MP, so these are pretty fine pixels. I'm not sure if I can bin 2x2 etc with a Bayer sensor? I know you can do this with Mono astro cams. 

Certainly a good thing to point out to me though, and I agree you can do basic DSO imaging with a basic but sturdy mount as long as you're aware of how to get round periodic error. 

I don't know. I get paid tomorrow. I didn't want to stretch my budget as there are other things to buy, but if an extra 200 quid made a difference I can't over look how little this is in the scheme of things. Our replacement front door cost nearly 1800!

[vlaiv]

4 minutes ago, Lockie said:

You're right. It's certainly equally about how fine the camera pixels are as well as the focal length. The combination of which giving the sample rate. My Fuji mirrorless has a weak IR filter so I'll probably use that over my Pany GH3. The Fuji also has the larger APS-C sensor at 24MP, so these are pretty fine pixels. I'm not sure if I can bin 2x2 etc with a Bayer sensor? I know you can do this with Mono astro cams. 

Certainly a good thing to point out to me though, and I agree you can do basic DSO imaging with a basic but sturdy mount as long as you're aware of how to get round periodic error. 

I don't know. I get paid tomorrow. I didn't want to stretch my budget as there are other things to buy, but if an extra 200 quid made a difference I can't over look how little this is in the scheme of things. Our replacement front door cost nearly 1800!

I think it is good info regardless of what your final choice may be.

Bayer matrix is a bit different, but can also be binned in very similar way to mono CMOS data. First thing to realize is that OSC sensors have lower sampling rate by factor of x2 in comparison to mono sensors of same pixel size (this is because pixels are spaced twice the distance if you look at individual colors - where green is thought as green1 and green2, regardless if they have same filter and end up in same channel). Once you debayer your image like that - by splitting it into channels, you can then further bin each channel by certain factor as if it was mono image (because it is really at that point). This will of course give you twice lower sampling rate than you calculated in the first place - and twice lower pixel count.

In fact color sensors have "full resolution" because algorithms make up missing pixels anyway (interpolate in certain way). You can do the same if you want with your final image - just enlarge it x2 (but you won't get any more detail by doing so either way - by debayering with interpolation or with resizing final result).

[Chris]

4 minutes ago, vlaiv said:

I think it is good info regardless of what your final choice may be.

Bayer matrix is a bit different, but can also be binned in very similar way to mono CMOS data. First thing to realize is that OSC sensors have lower sampling rate by factor of x2 in comparison to mono sensors of same pixel size (this is because pixels are spaced twice the distance if you look at individual colors - where green is thought as green1 and green2, regardless if they have same filter and end up in same channel). Once you debayer your image like that - by splitting it into channels, you can then further bin each channel by certain factor as if it was mono image (because it is really at that point). This will of course give you twice lower sampling rate than you calculated in the first place - and twice lower pixel count.

In fact color sensors have "full resolution" because algorithms make up missing pixels anyway (interpolate in certain way). You can do the same if you want with your final image - just enlarge it x2 (but you won't get any more detail by doing so either way - by debayering with interpolation or with resizing final result).

vlaiv, you know your stuff!

[RobertI]

I have always suspected the 130PDS or the 150PDS are the closest you can get to a scope for both imaging and visual. Not everyone likes newts on EQ mounts but these scopes are in rings so you can rotate the scope to get the eyepiece to a comfortable angle which I think should help. Another plus is that I can buy the scope off you when you upgrade later on. 😁😁

[Chris]

23 minutes ago, RobertI said:

I have always suspected the 130PDS or the 150PDS are the closest you can get to a scope for both imaging and visual. Not everyone likes newts on EQ mounts but these scopes are in rings so you can rotate the scope to get the eyepiece to a comfortable angle which I think should help. Another plus is that I can buy the scope off you when you upgrade later on. 😁😁

lol as per usual then Well It has been a while since I've sold you something   

I find Newts up to 6" pretty easy on an EQ mount as long as you have the focuser opposite the counter weight bar you can reach the focuser from any position the telescope sits in. 

 

 

[Skyline]

The 130PDS with EQ5 Pro.

The choice can only lay with you Chris, whatever you choose - Enjoy !

[Chris]

I do actually have this old mains powered RA driven beast in the garage. It's a bit on the crude side with no polar scope and the massive RA axis is based on a friction plate. It's at least eq6 class in terms of payload and is designed  specifically for a 6"f8 Newtonian looking at the integrated rings and pillar height.

I've never tried it with a scope as I picked it up cheap and it's just been stored since, so it's a gamble, but I could pick up a 6" f8 Newt from FLO for £185 to cover the lunar planetary side of things? Or I could flog it to add a little to the budget. 

Not exactly mobile though hmm

Edited December 20, 2019 by Lockie

[vlaiv]

18 minutes ago, Lockie said:

I've never tried it with a scope as I picked it up cheap and it's just been stored since, so it's a gamble, but I could pick up a 6" f8 Newt from FLO for £185 to cover the lunar planetary side of things?

That could well be the solution to planetary and lunar needs for both visual and imaging.

Why don't you give it a test run? No need to put scope on it - just plug it in and see if it moves. If it moves, it is probably good enough for both visual and planetary AP. For planetary AP you don't really need any sort of precision in your mount. As long as it keeps planet somewhere in FOV of camera - you are good.

I imaged planets with Eq2 with simple DC motor that had potentiometer to regulate tracking speed - it worked well.

If you do that, you still have something like £500 of your budget to put towards AP, and in that case, it's worth checking out AzGti with EQ accessories (counterweight and wedge, although you can use photo head for wedge - it won't have precise polar alignment and it needs to be rather heavy duty to support both mount and scope / lens - but maybe you have one lying around) and maybe a small scope - like 130pds or small refractor?

[Chris]

46 minutes ago, vlaiv said:

That could well be the solution to planetary and lunar needs for both visual and imaging.

Why don't you give it a test run? No need to put scope on it - just plug it in and see if it moves. If it moves, it is probably good enough for both visual and planetary AP. For planetary AP you don't really need any sort of precision in your mount. As long as it keeps planet somewhere in FOV of camera - you are good.

I imaged planets with Eq2 with simple DC motor that had potentiometer to regulate tracking speed - it worked well.

If you do that, you still have something like £500 of your budget to put towards AP, and in that case, it's worth checking out AzGti with EQ accessories (counterweight and wedge, although you can use photo head for wedge - it won't have precise polar alignment and it needs to be rather heavy duty to support both mount and scope / lens - but maybe you have one lying around) and maybe a small scope - like 130pds or small refractor?

Good call. I've removed the counter weight so it's more balanced, and I'll leave it running for a few hours to see how well it moves. If all looks good I'll place an order for the 150PL. I've been paid for this month so I've transferred an extra couple of hundred over into paypal so I can buy this scope, and the original budget will be intact purely for a small DSO imaging rig if needed

I have a decent Newer ball head for photography, so I can first try piggy backing my camera on top of the 150PL for wide field to see how it fairs? I don't think the wind would move this mount like it would an EQ5. It may track ok for 200mm or 4"/pixel if I can rig up a sight tube for PA. The only downside is that it's the kind of mount that's better off in a fixed location. It's super heavy and wide at the base lol If it works ok I could probably knock up a little shed with a slidey roof with the remaining budget. If not it will obviously get go back into plan A. 

Well at least now I've finally decided to buy something!   (Assuming the mount works!) 

[Chris]

Order placed! The mount appears to work fine so hit the button on the 150pl Newt. Saturday delivery wasn't much more so if I'm very lucky I could have it to test out soon