Field Flattener for ST80

[spillage]

I think if you have purchased very expensive filters why waste your time using the st80. Its like buying Ferrari and sticking budget tyres on it. Yes good quality filters are important but I would say so is the rest of your gear. I think you can purchase wisely but you still need a certain standard of kit.

Its the same as spending three thousand pounds on a scope and sticking it on a low end mount. 

[Dave In Vermont]

GSO has several adaptors - including one that fits the ST80. I have an ST80 I outfitted with mine. Fits like a glove!

Dave

 

 

 

[vlaiv]

Just to add, my ST102 while optically ok for visual, has aberration that might impact NB imaging - I noticed a bit astigmatism in red part of spectrum, so also check the scope if it is diffraction limited in all bands that you plan to image.

Well you don't really need to do that, but that might be another thing that you will notice on your images - slightly misshapen stars - and it might be because of poor optics.

[TareqPhoto]

1 minute ago, tooth_dr said:

I knew you would say that, it was just an example.  How do I put it - the ST80 is not a scope for imaging its for visual or guiding

Yes it is, but it can be for imaging not in APO or similar class, believe me, i saw bad examples done from APO quality ones, and i saw some nice decent from ST80, so it is all about how to do things as acquisition and stacking and processing, and if i can't get good [i said good, not perfect or excellent] results of DSO with ST80 then i can always use it for the moon and the sun, don't tell me it isn't possible at all, i saw very nice lunar image from ST80.

And as long i keep practicing with it, i can learn so one day when i get an APO then my ST80 will turn to guiding scope.

[TareqPhoto]

1 minute ago, Dave In Vermont said:

GSO has several adaptors - including one that fits the ST80. I have an ST80 I outfitted with mine. Fits like a glove!

Dave

 

 

Perfect, that is the one i should get then, thank you very much!

[parallaxerr]

8 minutes ago, TareqPhoto said:

Thank you very much for your post, i was waiting something like that, so if you confirm that MPCC is as good as any flattener to be used for ST80 then i can go for it, i thought the coma corrector is only used for reflectors such as SCT/Newt/Mak...etc, didn't know it can be used for Refr and do the same job as flattener, this is a relief, and to make it even more relief, one dy later i will buy a reflector of whatever kind which may need a coma corrector, so it is like i have an item that can be used later for something else, but you are the only one mentioned to me for now about coma corrector to be used with ST80. 

I got the idea for the MPCC here - http://www.stark-labs.com/craig/page9/WO66SD/WO66SD.html

It works great for me at F5, so I see no reason why the ST80 @F5 should be any different.

Quote

I did shoot with this scope and Ha filter, i didn't see CA at all because it is a mono, and later if i added RGB i don't know if that CA will be there too, or is that CA only with color[OSC] cameras?

It may be possible to add RGB and get better results than OSC, BUT the blue channel will have a different image scale which will need matching to the G+R channels before combining.

Quote

I do have Baader Contrast Booster which is designed to kill that CA, i can use it for some shots and added to Ha or NB filters, i never asked about CA solution here, my only questions were about focuser and flattener for field curvature, i never mentioned CA anywhere, but you only mentioned it for me.

I only mention it as an aside note to make a point to the naysayers, I apologise.

[TareqPhoto]

2 minutes ago, vlaiv said:

Just to add, my ST102 while optically ok for visual, has aberration that might impact NB imaging - I noticed a bit astigmatism in red part of spectrum, so also check the scope if it is diffraction limited in all bands that you plan to image.

Well you don't really need to do that, but that might be another thing that you will notice on your images - slightly misshapen stars - and it might be because of poor optics.

I can upload and give your RAW files i have of targets done with ST80 to check out, i really don't know how to stack successfully, i asked someone in another forum and he did it for me, it was nice, so that i got the courage to do more if i did things better way, if you can stack and process better than him then i may see even better results than his.

In all cases, i will accept all results coming out of this ST80, because i know it is not for imaging mainly, but all results will be just as practice, it is F5 so this will give me some advantages, and to be honest, i didn't see anyone tried this scope with a mono cooled camera so we can judge, all the results done with DSLR, even if i have an APO triplet i won't use DSLR, it won't match the quality of my AStro cooled camera, and i even didn't see some using this scope with astro camera and filters for DSO, maybe only for lunar or the sun, so until i see someone using this scope with a mono cooled camera with filters as results then i won't judge it yet, and why this scope will be bad compared to another Achro scopes larger and slower then?

[Dave In Vermont]

Many people take great photo's using the ST80. You can take out most violet-fringing through processing. They are quite capable little beautys!

Dave - Happy owner & user.

[TareqPhoto]

1 minute ago, Dave In Vermont said:

Many people take great photo's using the ST80. You can take out most violet-fringing through processing. They are quite capable little beautys!

Dave - Happy owner & user.

True, so this fringing or CA is my least problem here, even vignetting isn't my main problem, as long i get images with problems i will be fine, it is a sign that i can have something in my bad LP area, so later i can buy an APO when i can afford it for imaging, if my ST80 will be able to get something, then no doubt with APO i can do more, and who knows, i may buy something else such as 130PDS which sounds a good scope for imaging, i saw nice results from it with OSC cameras, i can't imagine how good it will be with mono camera and filters then, but before i do that i can wait and give that ST80 more try, buying a focuser and/or corrector isn't a big deal here, it won't cost me as much as an APO triplet which i may spend for accessories to go with it anyway.

I am thinking about getting a solar filter for this ST80, sounds it is a good focal length or aperture for that, and the moon is sooner will be followed once i buy a planetary camera color, i will try with my mono camera and ROI, all will be on time.

[Dave In Vermont]

I have a great Solar-Filter for mine - made by Rainboy-Symphony. Gives a very nice orange Solar-disc. Easy on the eyes imho.

You're on your way!

Dave

[TareqPhoto]

2 minutes ago, Dave In Vermont said:

I have a great Solar-Filter for mine - made by Rainboy-Symphony. Gives a very nice orange Solar-disc. Easy on the eyes imho.

You're on your way!

Dave

Link for the solar filter?

WOW, i can't wait to put my hand on that filter, the sun here in my country i see it more than my wife and my kids, hehehe, so you have the idea what do i mean.

Thank you very much!

[Dave In Vermont]

These are made by Rainbow-Symphony. Very inexpensive, too:

http://www.telescope.com/Accessories/Telescope-Eyepiece-Filters/Orion-E-Series-Safety-Film-Solar-Filters/pc/-1/c/3/sc/48/e/83.uts

Look around for such over there if you wish. Orion-USA does ship international though - if you need that.

Dave

[vlaiv]

16 minutes ago, TareqPhoto said:

I can upload and give your RAW files i have of targets done with ST80 to check out, i really don't know how to stack successfully, i asked someone in another forum and he did it for me, it was nice, so that i got the courage to do more if i did things better way, if you can stack and process better than him then i may see even better results than his.

In all cases, i will accept all results coming out of this ST80, because i know it is not for imaging mainly, but all results will be just as practice, it is F5 so this will give me some advantages, and to be honest, i didn't see anyone tried this scope with a mono cooled camera so we can judge, all the results done with DSLR, even if i have an APO triplet i won't use DSLR, it won't match the quality of my AStro cooled camera, and i even didn't see some using this scope with astro camera and filters for DSO, maybe only for lunar or the sun, so until i see someone using this scope with a mono cooled camera with filters as results then i won't judge it yet, and why this scope will be bad compared to another Achro scopes larger and slower then?

I agree, that would be the best approach - just give it a go, and practice your skills.

In general F5 achro will be at disadvantage to slower scope in terms of optical quality. Field curvature will be stronger, CA will be worse (this is not an issue for you), and optical correction will be worse. It is simply harder to figure fast lens to good optical quality then slow one.

[TareqPhoto]

3 minutes ago, Dave In Vermont said:

These are made by Rainboy-Symphony. Very inexpensive, too:

http://www.telescope.com/Accessories/Telescope-Eyepiece-Filters/Orion-E-Series-Safety-Film-Solar-Filters/pc/-1/c/3/sc/48/e/83.uts

Look around for such over there if you wish. Orion-USA does ship international though - if you need that.

Dave

It will be hard for me to find the right one from Orion store, i tried to avoid them before because i don't see them support international shipping to my country, unless they changed that, but i will give them a try if i find item i need.

Also, i don't know if i should get the glass filter or film filter, everywhere i read favor the film over the glass, i never thought that the glass will be less slightly performance than the film one, but i can always go with film filter and never look back, and being cheap then i can buy more than 1 for backup if needed.

Thanks!

[Dave In Vermont]

Last I checked they do ship international. And they only had 2 sizes of the filter - the larger fitting the ST80. The smaller one fits a 50mm finder-scope. ButI just remove mine altogether and use a Sunfinder (HelioPod) to locate and center the Sun. Neat and easy!

Dave

[TareqPhoto]

5 minutes ago, vlaiv said:

I agree, that would be the best approach - just give it a go, and practice your skills.

In general F5 achro will be at disadvantage to slower scope in terms of optical quality. Field curvature will be stronger, CA will be worse (this is not an issue for you), and optical correction will be worse. It is simply harder to figure fast lens to good optical quality then slow one.

I see, faster will magnify the issues then, good to know, thanks for this info, but with APO triplet why they look at faster ones then, because it is APO with better optics?

I posted this image before somewhere here, but i post it again just to show an example, i am very happy that i can get that level with ST80 even i didn't give it better settings and preparation.

https://scontent.ffjr1-2.fna.fbcdn.net/v/t1.0-9/21751936_1866354983675160_3444615636205912172_n.jpg?oh=39470e5c243cb598de4ccecef59f01ea&oe=5A81907F

Not guided and no good PA so very short exposures, and i think the member didn't stack the RAW files, i think he said he played the single RAW file out of many, so i can push that even more later if i have to give it more care.

[vlaiv]

1 minute ago, TareqPhoto said:

I see, faster will magnify the issues then, good to know, thanks for this info, but with APO triplet why they look at faster ones then, because it is APO with better optics?

I posted this image before somewhere here, but i post it again just to show an example, i am very happy that i can get that level with ST80 even i didn't give it better settings and preparation.

https://scontent.ffjr1-2.fna.fbcdn.net/v/t1.0-9/21751936_1866354983675160_3444615636205912172_n.jpg?oh=39470e5c243cb598de4ccecef59f01ea&oe=5A81907F

Not guided and no good PA so very short exposures, and i think the member didn't stack the RAW files, i think he said he played the single RAW file out of many, so i can push that even more later if i have to give it more care.

APOs are fast because they can make them fast - usually to control CA in doublets and ED doublets you have long to medium FL to make them good - like F10 and above for regular doublets and F7-F9 for ED doublets. APOs on the other hand don't have problem with CA if properly executed, so as they were aimed for photographers and most demanding observers in the past - they tend to be short in order to have higher speed instrument (photography wise), and also form factor - easier to mount and carry. Optical quality on the other hand is reflected in price of APOs, so yes, they are optically really good. It would not make sense to make expensive telescope that is not good optically - who would buy it?

Here are examples of what you might get with achromat when imaging. Mind you, these two were taken small sensor OSC chip - so they are mosaics and because telescope was stopped down, SNR is not that good on them, so they lack depth, but do show sharpness that you can achieve with this kind of scopes (I believe first one is 3x3 mosaic while second one is 2x2) :

 

[TareqPhoto]

7 minutes ago, vlaiv said:

APOs are fast because they can make them fast - usually to control CA in doublets and ED doublets you have long to medium FL to make them good - like F10 and above for regular doublets and F7-F9 for ED doublets. APOs on the other hand don't have problem with CA if properly executed, so as they were aimed for photographers and most demanding observers in the past - they tend to be short in order to have higher speed instrument (photography wise), and also form factor - easier to mount and carry. Optical quality on the other hand is reflected in price of APOs, so yes, they are optically really good. It would not make sense to make expensive telescope that is not good optically - who would buy it?

Here are examples of what you might get with achromat when imaging. Mind you, these two were taken small sensor OSC chip - so they are mosaics and because telescope was stopped down, SNR is not that good on them, so they lack depth, but do show sharpness that you can achieve with this kind of scopes (I believe first one is 3x3 mosaic while second one is 2x2) :

 

Fair enough, as long they added quality elements in APO scopes so then they better make them fast, but they are still having the problem of field curvature even with F5 APO triplet expensive one.

Those examples are great to have as starter, I will be happy with either or both for mine, so i don't have issues using Achromatic scopes for practice.

I forgot one thing to add, i do have Canon lenses, i saw nice results done from some of those lenses, i do have 100-400 as the longest focal length with bare lens, but i do have Canon 300mm f2.8L IS mk1, one of finest lenses from Canon, and i can use it with 1.4x to have 420mm and F4, i can stop it down to F5 or F6.3 to reduce some issues, but the problem is that i don't know how to piggyback a guide scope on any Canon lenses if i have to use one for imaging, i think the lenses are designed to prevent CA anyway, i even have Canon 70-200 f2.8L IS II which is known as one of the best zooms from Canon so far, means it is good for CA issue, i saw many reviews and tests in that regard showing no to very minimal CA, so i can always give Canon lenses a try over ST80 and before getting any APO scopes, also Sigma have many lenses in APO series, aren't those good enough as APO scopes? 

[vlaiv]

Honestly I don't know much about lenses and their performance for astro photography. I did however hear that good lens for astro work is Samyang 135mm F/2. There are more then a couple of threads on this forum with images done using this lens, so check it out.

As for mounting, probably easiest thing to do is to mount lens & camera piggy back on ST80 and use ST80 for guiding.

[Red Dwarfer]

Good luck with all of this , Tareq 

I'm just glad I only do visual astronomy ??

[TareqPhoto]

16 minutes ago, vlaiv said:

Honestly I don't know much about lenses and their performance for astro photography. I did however hear that good lens for astro work is Samyang 135mm F/2. There are more then a couple of threads on this forum with images done using this lens, so check it out.

As for mounting, probably easiest thing to do is to mount lens & camera piggy back on ST80 and use ST80 for guiding.

You mean i put the lens on the scope and mount the scope on the mount and using the lens with camera and use ST80 as guide scope? in fact i wanted to put that ST80 on the lens, and i don't know how, this is why i asked about piggyback.

[TareqPhoto]

4 minutes ago, Red Dwarfer said:

Good luck with all of this , Tareq 

I'm just glad I only do visual astronomy ??

Thank you very much!

I miss a lot without imaging, hahaha

[vlaiv]

51 minutes ago, TareqPhoto said:

You mean i put the lens on the scope and mount the scope on the mount and using the lens with camera and use ST80 as guide scope? in fact i wanted to put that ST80 on the lens, and i don't know how, this is why i asked about piggyback.

Yes, other way around is much simpler and better - so just add another dovetail bar on top side of the rings, and then bolt your lens - T2 camera adapter to it and you are all set.

Here is image I found on net depicting what it would look like - just replace DSLR with QHY163 ....

[TareqPhoto]

For ordering from Orion site [Telescope.com] if you checked out this link you will see that they aren't shipping to many international countries such as my country, and funny they stated to use the local dealer which i tried, very bad prices and not many items available, so that i ignored Orion completely.

http://www.telescope.com/custserv/custserv.jsp?pageName=ShippingAndDelivery&src=footer2

[TareqPhoto]

2 minutes ago, vlaiv said:

Yes, other way around is much simpler and better - so just add another dovetail bar on top side of the rings, and then bolt your lens - T2 camera adapter to it and you are all set.

Here is image I found on net depicting what it would look like - just replace DSLR with QHY163 ....

How can i apply the Ha filter then if i use a lens with QHY163M, the adapters to connect the camera to lens doesn't have any 1.25" thread, not the one i have already.