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Sharpstar 61 EDPH II APO Chromatic Abberation?

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43 replies to this topic

#26 F.Meiresonne

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Posted 11 October 2020 - 02:38 PM

About 60 exposures, 1 minute, unguided, unmodded DSLR Canon 800D.

 

no filters.



#27 F.Meiresonne

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Posted 11 October 2020 - 02:43 PM

This is a jpg , one the the 60, untouched and higly enlarged.(i Always take RAW + JPG)

 

The photo above is stacked off course, but the jpg here is(cut out of a brighter star) untouched and comes straight from the camera.

Attached Thumbnails

  • 61edph.JPG

Edited by F.Meiresonne, 11 October 2020 - 03:04 PM.


#28 F.Meiresonne

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Posted 11 October 2020 - 02:53 PM

I finally had the opportunity to setup everything and start testing the go-to, which seems to work relatively well. However, my photos of the Pleiades have these purple halos around them and I can't help but wonder if I got a dud scope, or if it really matters and I can edit this out and correct at a later point. I posted here because I want to know if this is specifically a fault with the telescope and I do not have any eye pieces to just pop into the scope to check myself.

This is just a 30 second exposure and it seems to be visible in other stars, not red ones or orange ones, but blue ones specifically.

Very disturbing picture. I don't think it should look like this...see my picture of M35, made by the doublet version of this scope. IMO something is not right with the scope...



#29 mmalik

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Posted 11 October 2020 - 04:37 PM

See below a picture taken with the doublet version...

Let's be clear; doublet version of what? I presume it is not Sharpstar 61 EDPH II; if not then let's not confuse the matter. Regards


Edited by mmalik, 11 October 2020 - 04:38 PM.


#30 Barologuy

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Posted 11 October 2020 - 05:49 PM

I messaged Sharpstar and I'm waiting to hear back. I'll keep you updated!

#31 F.Meiresonne

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Posted 12 October 2020 - 12:59 AM

Let's be clear; doublet version of what? I presume it is not Sharpstar 61 EDPH II; if not then let's not confuse the matter. Regards

No it is the sharpstar 61 mm EDPH version 1. A doublet. Only very recently Sharpstar came out with a triplet version. Same FF/FR, same F, same outfit

 

That is why I cannot understand the doublet seems to give better views that the triplet here. You should expect just the opposite.


Edited by F.Meiresonne, 12 October 2020 - 01:01 AM.


#32 mmalik

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Posted 12 October 2020 - 01:18 AM

Thanks for clarifying; I didn't know. Regardless, they are two different sopes/designs. Agree with your assessment though. Regards


Edited by mmalik, 12 October 2020 - 01:33 AM.


#33 anat

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Posted 16 October 2020 - 08:02 PM

I messaged Sharpstar and I'm waiting to hear back. I'll keep you updated!

Any words from Sharpstar on this issue?

Sent from my SM-N960F using Tapatalk

#34 Barologuy

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Posted 16 October 2020 - 09:39 PM

No word from Sharpstar.

It could be related to the fact that I have a larger scope mounted on top of that may be causing the lens problems, but when I stack them generally the purple rings go away and it seems to go away as the weather chills down.

Not sure what that means though.

#35 F.Meiresonne

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Posted 17 October 2020 - 09:00 AM

How do you focus?



#36 Barologuy

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Posted 17 October 2020 - 09:28 AM

How do you focus?



Typically I have a DSLR connected and then I focus as best as possible using camera features, then I place a Bahtinov mask over the OTA to make the final adjustments, usually while on max camera "zoom" on the image.

And I refocus when I slew to a new object.

#37 andysea

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Posted 17 October 2020 - 06:48 PM

I agree with what others have said. It looks like CA.  I might have missed it but did you try the same target without the focal reducer?

That would be the first step to troubleshoot the system. You will get field curvature but that is expected without a corrector.

Make sure that you have some of the bright stars in the center of the image.



#38 Barologuy

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Posted 18 October 2020 - 01:28 AM

I agree with what others have said. It looks like CA. I might have missed it but did you try the same target without the focal reducer?
That would be the first step to troubleshoot the system. You will get field curvature but that is expected without a corrector.
Make sure that you have some of the bright stars in the center of the image.


I did not try it without a focal reducer, I'll update this next time I have clear skies. Lots of smoke right now, the Colorado fires are about 5 miles from my house!

#39 F.Meiresonne

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Posted 18 October 2020 - 05:03 AM

I agree with what others have said. It looks like CA.  I might have missed it but did you try the same target without the focal reducer?

That would be the first step to troubleshoot the system. You will get field curvature but that is expected without a corrector.

Make sure that you have some of the bright stars in the center of the image.

That would be indeed a good test

 

Or shoot the moon, when she is bright, to see i you get purple or yellow rims....


Edited by F.Meiresonne, 18 October 2020 - 05:05 AM.


#40 alphatripleplus

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Posted 18 October 2020 - 10:10 AM

Stay safe with those fires nearby! I am also curious  to see what the results are without the reducer.



#41 byang

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Posted 24 October 2020 - 10:21 PM

No word from Sharpstar.

It could be related to the fact that I have a larger scope mounted on top of that may be causing the lens problems, but when I stack them generally the purple rings go away and it seems to go away as the weather chills down.

Not sure what that means though.

It is almost 2 weeks. Have u gotten a reply from Sharpstar?



#42 Barologuy

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Posted 24 October 2020 - 11:37 PM

It is almost 2 weeks. Have u gotten a reply from Sharpstar?


I have still not gotten a reply from Sharpstar regarding the CA.

I'll also note that viewing without the Reducer and Flattener, and removing all other equipment made no difference, the stars are still purple.

Edited by Barologuy, 24 October 2020 - 11:39 PM.


#43 byang

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Posted 25 October 2020 - 08:36 PM

I have still not gotten a reply from Sharpstar regarding the CA.

I'll also note that viewing without the Reducer and Flattener, and removing all other equipment made no difference, the stars are still purple.

Thanks for the update. Do u mean that the same was observed when the scope was used for visual?

 

I have gotten same day response from Sharpstar when I sent them an enquiry in July: sales@sharpstar-optics.com. Was it the same email that u sent to? You may want to email them again and ask if they have received your earlier email and are studying the problem, and to provide a date where you may possibly hear from them on the outcome. Giving them the serial number of your scope or QC report may also be useful for the investigation at their end. Just a suggestion :-)



#44 Barologuy

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Posted Yesterday, 11:53 PM

Thanks for the update. Do u mean that the same was observed when the scope was used for visual?

 

I have gotten same day response from Sharpstar when I sent them an enquiry in July: sales@sharpstar-optics.com. Was it the same email that u sent to? You may want to email them again and ask if they have received your earlier email and are studying the problem, and to provide a date where you may possibly hear from them on the outcome. Giving them the serial number of your scope or QC report may also be useful for the investigation at their end. Just a suggestion :-)

I am reaching out through my vendor and I will hopefully know more later this week.




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