Orion Optics AG12 astrograph - First Light! - new Starfire comparison

[avandonk]

Here you go Mike an animated GIF 10MB

http://d1355990.i49.quadrahosting.co.../mikefinal.gif


This is an unfair test to the AG12, but the new AG12 can only get better with no Moon and better seeing.

Bert

[strongmanmike (Michael)]

Originally Posted by avandonk

Here you go Mike an animated GIF 10MB

http://d1355990.i49.quadrahosting.co.../mikefinal.gif


This is an unfair test to the AG12, but the new AG12 can only get better with no Moon and better seeing.

Bert

On ya Bert, thanks for that ...I knew you would

The comparison is a bit better than the last one huh?...note to self - watch your noise reduction!

How do you do these giff animations by the way?

Mike

[avandonk]

To make these GIF animations I use Registar to excise exactly the same image size and content from each image..

For the last animated gif I cropped the Starfire image and AG12 image from your pair.

I then used the starfire image as reference to register the AG12 image. The trick is then to combine average the intersection of these two images. I then slightly crop this combination.

Using this cropped combination as the reference I then run Registar again.
This time I intersection combine the reference image with a weight of 0.0001 (click on combine and right click on reference image to insert value of 0.0001) to the wanted image weight of 1.0 or default.

Repeat for all images. You now have perfectly aligned images with exactly the same size dimensions in pixels.

Convert to gifs with PS.

I use a program called UnFREEz from here to make the animation

http://www.whitsoftdev.com/unfreez/

Just highlight the gifs for the animation and drag to the UnFREEz window and make sure you put the cursor on frame1.

You can then insert the delay between frames.


Hope this is clear if not feel free to ask any questions.


Bert

[Satchmo]

Hi Michael

A 12" telescope has an angular resolution twice that of a 6" telescope. Takahashi scopes run by the same laws of physics as any other Assuming good optics ,the similarity in resolving power in the comparison shot taken with twice the aperture at similar FL, must come down to the level of pixel under -sampling of the airy pattern and /or inclement seeing conditions. An unobstructed refracter will have less light in the outer rings than an obstructed scope , but you would need a greater level of pixel over- sampling of the airy pattern to pick the difference. Still its remarkable to get so much quality data in 20 minutes compared to 90 minutes.

Is your 'scopes native focal ratio F3.8 or F4 ?

[strongmanmike (Michael)]

Originally Posted by Satchmo

Hi Michael

A 12" telescope has an angular resolution twice that of a 6" telescope. Takahashi scopes run by the same laws of physics as any other Assuming good optics ,the similarity in resolving power in the comparison shot taken with twice the aperture at similar FL, must come down to the level of pixel under -sampling of the airy pattern and /or inclement seeing conditions. An unobstructed refracter will have less light in the outer rings than an obstructed scope , but you would need a greater level of pixel over- sampling of the airy pattern to pick the difference. Still its remarkable to get so much quality data in 20 minutes compared to 90 minutes.

Is your 'scopes native focal ratio F3.8 or F4 ?

Yeh, probably all makes sense Mark (it's an Astrophysics APO by the way, not Takahashi). The untouchable optical quality of the Starfire makes it a great standard test platform to make practical (as oposed to theoretical) comparisons (under enlargement) with any scope in my opinion ie if you are getting similar looking images then your scope must be bloody good

- The FL of the Starfire is 1300mm comapared to 1181mm for the AG12
- The image scale with the ProLine16803 and the Starfire is 1.4"/pix compared to 1.6"/pix with the AG12
- The mirror in the AG12 is a native F4 and the Wynne corrector has a 0.95X reduction

Mike

[strongmanmike (Michael)]

Originally Posted by avandonk

To make these GIF animations I use Registar to excise exactly the same image size and content from each image..

<snip>

Hope this is clear if not feel free to ask any questions.


Bert

Cheers Bert very cool, much appreciated! .

I made my own comparison - bit smaller file size too so it's quicker to load but shows essentially the same thing...lots of impatient folks out there

Mike

[Rigel003 (Graeme)]

Sorry to not have commented on these earlier Mike. Looks like a great scope. The Omega Centauri image is just amazing! Probably the best of seen. When you're all up and running it's going to be scary good.

[CometGuy]

Mike,

Very envious of you, such a huge field of view! Is the Corrector/Reducer the Keller one or an AG design?

Terry

[Satchmo]

Originally Posted by strongmanmike

- The image scale with the ProLine16803 and the Starfire is 1.4"/pix compared to 1.6"/pix with the AG12

Thanks Mike- With most of the useful light of a 12" falling within an 0.75" circle, assuming good optics you will probably need to use a 2X converter and good seeing and guiding to exploit the resolution difference inherent between a 6" and 12" 'scope with this camera.

[Leonardo70 (Leonardo Orazi)]

Congratulations Mike for the first light ... the cluster are simply wonderful. Wait for the next shots...

Great work on squared the 16803 ... i'm scared only to think about

I'm looking for the 8" AG ... budget are short

[avandonk]

Originally Posted by strongmanmike

Cheers Bert very cool, much appreciated! .

I made my own comparison - bit smaller file size too so it's quicker to load but shows essentially the same thing...lots of impatient folks out there

Mike

It is not often the mature age student can help the master.

So show us your gifs!

Bert

[strongmanmike (Michael)]

Originally Posted by Rigel003

Sorry to not have commented on these earlier Mike. Looks like a great scope. The Omega Centauri image is just amazing! Probably the best of seen. When you're all up and running it's going to be scary good.

No worries Graeme, gee glad you liked the Omega Cen shot, it is so big I guess we don't often see it swimming in a sea of stars

Originally Posted by CometGuy

Mike,

Very envious of you, such a huge field of view! Is the Corrector/Reducer the Keller one or an AG design?

Terry

Ah yes we are all green with envy of others at some stage in this hobby huh? . The corrector is not the Keller variety, it is larger and has 4 ellements in three groups and the field specs are a little better

Originally Posted by Satchmo

Thanks Mike- With most of the useful light of a 12" falling within an 0.75" circle, assuming good optics you will probably need to use a 2X converter and good seeing and guiding to exploit the resolution difference inherent between a 6" and 12" 'scope with this camera.

Yes unfortuunately you are right hence my jsutification to use the Starfire as the standard candle in this situation

Originally Posted by Leonardo70

Congratulations Mike for the first light ... the cluster are simply wonderful. Wait for the next shots...

Great work on squared the 16803 ... i'm scared only to think about

I'm looking for the 8" AG ... budget are short

Hi Leo

Getting the image plane perfectly square has not been acheived quite yet but it is close, I collimated using the Catseye tools only and this got it pretty close so the accuracy of the OTA and image train build must be very good and the images can only get better from here really
An AG8 huh? nice idea, very portable and able to be used on a smaller mount too

Originally Posted by avandonk

It is not often the mature age student can help the master.

So show us your gifs!

Bert

Old man and the (imaging) Sea

My gifs are here

[gregbradley]

Congratulations Mike. A fabulous start. The Omega Centauri is a spectacular image.

As mentioned the star distortions are trivial. I had the same problem over Easter with my TEC180 and I only just noticed it this morning whilst doing some processing. I thought my minor elongation in the corners was flexure but now I see it as more radial than that.

I put that down more to a spacing between the corrector and the camera rather than flex. Flex would be more one side only and would not be radial out from the centre. What I see in some of the images is slight radial elongation pointing out from the centre. That would most likely be caused by incorrect metal back distance for the corrector but only out by a tad and perhaps at the limit of the correctors corrected circle??

As I say I have seen the same on a few images with my TEC mainly using a Takashashi reducer which is not designed for the TEC. But also this last weekend using the TEC flattener. The Proline is a great camera but is also a fatso and weighs a lot. I did not see any coma using the Apogee U16M. I think my spacing is slightly off for my corrector. Mine is about the same elongation as yours.

If it were flex it probably would shift from one side of the image to other when you cross the meridian. Perhaps pack out your spacer with something to see if it makes any difference. I'd suggest it would be about 3-5mm out at a guess. In my case it may be 10mm out (I do have a spacer which I thought was for the ML8300 but perhaps I got that the other way round!).

Anyway a super start and that is a very interesting comparison with the AP152. Its showing that you can get similar data in half the time or less which was the whole point of that scope right?

Greg.

[Hagar (Doug)]

As I said in your other Post. Beautiful start with your new beast. You must be feeling better about it now.
I just wonder how hard it will be to collimate this fast a scope very well. Looks good so far.
Take a big breath and relax..... IT ALL WORKS.

Congratulations Mike.

[strongmanmike (Michael)]

Originally Posted by gregbradley

Congratulations Mike. A fabulous start. The Omega Centauri is a spectacular image.

As mentioned the star distortions are trivial. I had the same problem over Easter with my TEC180 and I only just noticed it this morning whilst doing some processing. I thought my minor elongation in the corners was flexure but now I see it as more radial than that.

I put that down more to a spacing between the corrector and the camera rather than flex. Flex would be more one side only and would not be radial out from the centre. What I see in some of the images is slight radial elongation pointing out from the centre. That would most likely be caused by incorrect metal back distance for the corrector but only out by a tad and perhaps at the limit of the correctors corrected circle??

As I say I have seen the same on a few images with my TEC mainly using a Takashashi reducer which is not designed for the TEC. But also this last weekend using the TEC flattener. The Proline is a great camera but is also a fatso and weighs a lot. I did not see any coma using the Apogee U16M. I think my spacing is slightly off for my corrector. Mine is about the same elongation as yours.

If it were flex it probably would shift from one side of the image to other when you cross the meridian. Perhaps pack out your spacer with something to see if it makes any difference. I'd suggest it would be about 3-5mm out at a guess. In my case it may be 10mm out (I do have a spacer which I thought was for the ML8300 but perhaps I got that the other way round!).

Anyway a super start and that is a very interesting comparison with the AP152. Its showing that you can get similar data in half the time or less which was the whole point of that scope right?

Greg.

Cheers Greg

Yes I tend to agree with you, the residule distortions although minor are enough to bug me and leave me thinking how much better still it could be. Allready snapping at the heels of Starfire for resolution, at least in the cetral 2/3 of the field.

How the spacing could be wrong puzzles me though as it appears to have been constructed exactly to the specs I provided Orion.?

I get the feeling that good collimation and alignment is relatively easy but the design makes getting the parameters perfectly set much harder..? had I not been so spoiled by the Starfire experience these shots would probably look essentially perfect

Yes I thought of packing out the spacer but what if it needs to be brought in..? I'll have to think on this

Originally Posted by Hagar

As I said in your other Post. Beautiful start with your new beast. You must be feeling better about it now.
I just wonder how hard it will be to collimate this fast a scope very well. Looks good so far.
Take a big breath and relax..... IT ALL WORKS.

Congratulations Mike.

Ah Dougie how true that is, how true that is...sighhhhhhh almost enough to become religious

I hope I am able to eeek that extra few % improvement out of the collimation asap...then I will be 100% happy

Mike

[gregbradley]

Perhaps double check all the measurements. Do you know the exact metal back distance for the corrector? The distance of the chip from the window of the Proline is on the FLI website. From memory it is something like 31mm. I need to check my setup also for this sort of thing.

Greg.

Originally Posted by strongmanmike

Cheers Greg

Yes I tend to agree with you, the residule distortions although minor are enough to bug me and leave me thinking how much better still it could be. Allready snapping at the heels of Starfire for resolution, at least in the cetral 2/3 of the field.

How the spacing could be wrong puzzles me though as it appears to have been constructed exactly to the specs I provided Orion.?

I get the feeling that good collimation and alignment is relatively easy but the design makes getting the parameters perfectly set much harder..? had I not been so spoiled by the Starfire experience these shots would probably look essentially perfect

Yes I thought of packing out the spacer but what if it needs to be brought in..? I'll have to think on this



Ah Dougie how true that is, how true that is...sighhhhhhh almost enough to become religious

I hope I am able to eeek that extra few % improvement out of the collimation asap...then I will be 100% happy

Mike

[Phil Hart]

very exciting mike.. i find the comparison with the starfire amazing!

it seems i've pushed my Tak Epsilon 160 past its limits recently - it's an awesome match for an APS-C DSLR which has been my bread and butter, but with larger format and/or small pixel CCD the corners don't hold up so well. so i'm impressed with the quality of this nearly as fast optical system on such a large chip. very impressed.

the one challenge i'll still be following is how well your flats work once you start really pushing the system..

thanks for sharing all the info..

Phil

[mithrandir (Andrew)]

... and it has an "Owner's Observations" box from our own strongmanmike - with photo.

[h0ughy (David)]

yes congrats Mike on the story in the mag.

[Zubenel (Wes)]

Somewhat of a post-script Mike but that image the antennae Galaxies is a cracker Mike.ya gotta be happy with that !! Makes me look towards a Newtonian for imaging ....

Cheers