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Has anyone heard of this scope before (Sharpstar 61 EDPH)?

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223 replies to this topic

#151 anat

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Posted 24 August 2020 - 12:17 AM

I had a very short time window to test my 61EDPH II and ASI533mc. I accidentally set Bin2x2. The uncropped image below looks clean and very flat. Flatter than RedCat51 I tested before. 

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Edited by anat, 24 August 2020 - 12:29 AM.


#152 F.Meiresonne

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Posted 24 August 2020 - 01:14 AM

 

Not quite got the spacing right yet because even though I measure 37mm (+18 fr the A7s), the stars in the corners suggest it's too far. Enjoying the Sharpstar quite a bit nonetheless. I'm hoping there's a flattener that works well at the native focal length.
 

 

In your M31 picture stars in the corner look pretty ok imo.

Do you use the dedicated flattener?



#153 gnarayan

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Posted 24 August 2020 - 02:00 AM

In your M31 picture stars in the corner look pretty ok imo.

Do you use the dedicated flattener?

Yes, the dedicated flattener that is bundled with the scope. I did whatever I could to suppress the elongation in the corners, but it's there in the raw frames and unfortunately not in the direction where adding shims will help.

I've tried it with a Baader M48 -> M42 adapter and Fotodiox astro M42 extension tube -> E-mount adapter, as well as a single piece generic (Tebru, but it's the same as Mugast and a bunch of other brands on Amazon) M48-> E mount adapter. Both adapters are 37mm (with calipers), which is right for E-mount for 55mm backfocus, which is the spec for the 0.8x reducer, but this is still too long apparently. Thankfully the back half of the reducer is just an extension tube with a filter holder, so I think I can replace it with some variable tube + filter wheel, but haven't sat down and figured out all the threads and spacing yet.



#154 UKalwayscloudy

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Posted 25 August 2020 - 12:20 AM

Gnaryan this is interesting. I haven’t got data from my 4/3 Hypercam yet as the Cooling isn’t behaving but will report when I can. If you are doing a custom build replacing the rear part of the reducer I went from M63 to M68 and then ran a Baader UFC rig including the variolock to be able to adjust the fine spacing. With the standard adapter does it still look like you are too long with a filter in place?

#155 gnarayan

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Posted 25 August 2020 - 12:46 AM

Gnaryan this is interesting. I haven’t got data from my 4/3 Hypercam yet as the Cooling isn’t behaving but will report when I can. If you are doing a custom build replacing the rear part of the reducer I went from M63 to M68 and then ran a Baader UFC rig including the variolock to be able to adjust the fine spacing. With the standard adapter does it still look like you are too long with a filter in place?

It'd be hugely appreciated if you have a parts list/a picture of the reducer with the Baader UFC setup! Might be worth doing going this route because getting filters into and out of the original FR's extension tube is a bit tricky.

Corner elongation is better with a filter installed in the original extension tube though (as expected) - I'd used it with an IDAS-LPS-P2 which I think is 2.5mm thick for the NGC7000 picture and didn't feel the need to crop as much as with M31. Will try it again this weekend if we have clear skies.


Edited by gnarayan, 25 August 2020 - 12:47 AM.


#156 OldManSky

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Posted 26 August 2020 - 11:26 AM

Thank you for replying! Could you recall which astronomical objects were your observing for making the comparison?

Mostly bright stuff (they are, after all, 60mm scopes!).  Andromeda.  Double cluster.  Pleiades.  I did look at Jupiter with both (and a 4mm Vixen Lanthanum eyepiece), but even with a 4mm eyepiece planets are still awfully darn small, so comparing fine planetary detail isn't really possible :)



#157 kel123

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Posted 26 August 2020 - 11:42 AM

Mostly bright stuff (they are, after all, 60mm scopes!).  Andromeda.  Double cluster.  Pleiades.  I did look at Jupiter with both (and a 4mm Vixen Lanthanum eyepiece), but even with a 4mm eyepiece planets are still awfully darn small, so comparing fine planetary detail isn't really possible smile.gif

Exactly. It is just a 60 mm scope which is more useful for wild field imaging than for visual. Of course it can be used for visual but barely. Hence, primarily for imaging and secondarily for visual.  


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#158 F.Meiresonne

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Posted 26 August 2020 - 12:07 PM

Yes indeed,allthough i could do a good job on birdwatching, being apo or near apo.

 

Actually i did test this, visualy , the doublet, could see no color.

 

But i bought it just for the wide field.

 

Idea is as follows : 61 EDPH very wide fields

                               76 EDPH wide fields

                              102 mm for just  fieldsgrin.gif

                               8 inchd RC (yet to come) narrow fields for smaller objects

 

That is  a bit the idea i have...

 

But the RC is not for any time soon,first i got to build more expertise and experience with AP


Edited by F.Meiresonne, 26 August 2020 - 12:11 PM.


#159 cddestins

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Posted 27 August 2020 - 05:34 AM

Hello, is the BF of 76 edph really 55mm in practice? Thank you

#160 gionk

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Posted 27 August 2020 - 07:10 AM

Hi, this thread is about the 61 EDPH and 61 EDPH II

#161 cddestins

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Posted 27 August 2020 - 08:08 AM

Hello, is the BF of 61 EDPH and 61 EDPH II really 55 mm in practice ? Thank you

#162 byang

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Posted 27 August 2020 - 08:53 AM

Thanks again! I was hoping that Moon was one of the objects that you observed when comparing the colour correction of the 2 scopes you mentioned earlier. I suspect the difference between the colour correction of the 2 scopes maybe subtle when viewing Jupiter at low power (indeed can't be over demanding with a 60mm scope) but for the Moon, I would love to hear comment on whether the view is totally void of CA! smile.gif

 

Mostly bright stuff (they are, after all, 60mm scopes!).  Andromeda.  Double cluster.  Pleiades.  I did look at Jupiter with both (and a 4mm Vixen Lanthanum eyepiece), but even with a 4mm eyepiece planets are still awfully darn small, so comparing fine planetary detail isn't really possible smile.gif



#163 F.Meiresonne

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Posted 27 August 2020 - 02:02 PM

Thanks again! I was hoping that Moon was one of the objects that you observed when comparing the colour correction of the 2 scopes you mentioned earlier. I suspect the difference between the colour correction of the 2 scopes maybe subtle when viewing Jupiter at low power (indeed can't be over demanding with a 60mm scope) but for the Moon, I would love to hear comment on whether the view is totally void of CA! smile.gif

Hm, i guess it did the test , but i can't recall, but i think i was colorless.in the doublet...

 

Will try to check it again...when the moon gets higher and the rain stops, which will not be any time soon i am afraid



#164 kel123

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Posted 27 August 2020 - 09:13 PM

Hello, is the BF of 61 EDPH and 61 EDPH II really 55 mm in practice ? Thank you

Let me try to help here . I guess no one has responded to your question because it lacks context. 

 55 mm is the back focus of the telescope when it is couple with the focal reducer. This scope comes, mostly bundled with the focal reducer, hence 55 mm should be the distance between the back flange of the reducer and the sensor of the camera. 



#165 F.Meiresonne

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Posted 28 August 2020 - 01:39 AM

Let me try to help here . I guess no one has responded to your question because it lacks context. 

 55 mm is the back focus of the telescope when it is couple with the focal reducer. This scope comes, mostly bundled with the focal reducer, hence 55 mm should be the distance between the back flange of the reducer and the sensor of the camera. 

cddestins has an issue with his FF/FR on a 76 edph.

 

See his thread : https://www.cloudyni...724886-76-edph/

 

i think it might be tilt..

 

Anyhow for the 61 and 76 edph distance 55 mm should be the distance to the sensor.


Edited by F.Meiresonne, 28 August 2020 - 01:40 AM.


#166 UKalwayscloudy

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Posted 01 September 2020 - 01:35 AM

Sorry off line for a few days. The 55mm bf is measured from the camera side end of the rear part of the reducer. You can unscrew that and then access the M63 thread in the main optical part of the reducer. From there the BF is 110mm.

The precise parts needed for the UFC depend a bit on which camera you use and its distance from the physical front of the camera. I use an M63-M68 adapter and M68 female reversing ring from TS optics to expand that M63 to M68 female, and then use the Baader UFC setup starting with the M68 male telescope side connector. Then the details depend on your camera, but it then goes

M68 telescope adapter
UFC extension tubes
Variolock
UFC chamber
Camera side adapter.

I’ve recently added the TS optics M68 rotator off the reverser and lowered the length of the UFC extensions.

So with a 17.5mm BF-use Hypercam 269c I’ve got the rotator with two 15mm tubes and a 5mm in the middle and the M42 camera side adapter.

#167 kel123

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Posted 01 September 2020 - 02:16 AM

cddestins has an issue with his FF/FR on a 76 edph.

See his thread : https://www.cloudyni...724886-76-edph/

i think it might be tilt..

Anyhow for the 61 and 76 edph distance 55 mm should be the distance to the sensor.


I see. There has to be something amiss with his imaging train. It might be tilt like you assumed or he might have a problematic focal reducer.

#168 UKalwayscloudy

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Posted 01 September 2020 - 04:27 AM

I know when I added my M68 rotator I had to be careful tightening it as it was easy to create a tilt. The Baader stuff is very good at keeping stuff parallel.

#169 cddestins

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Posted 01 September 2020 - 10:53 AM

Yes I have a tilt problem with 76 edph + asi 1600mm + filters. However, I also had a problem with focusing, at F / D 4.5 it is very sensitive and also sensitive to temperature variations. Every 0.5 degrees Celsius must enter the eyepiece holder by 4 steps zwo eaf.

#170 gonzothegreat

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Posted 03 September 2020 - 03:47 PM

How would such triplet compare to a Canon 200mm lens please? Or is there no comparison and this one trump the lens?



#171 Joe Bruessow

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Posted 05 September 2020 - 01:51 PM

I am hoping those of you who own this scope and reducer/flattener can help me out.  I have a Stellarvue SV60eds (60mm f5.5 fpl53 doublet).  I assumed this was the same exact scope and want to buy the 0.8x reducer/flattener for it. 

 

Unfortunately, when I did some measuring it doesn't look like it will thread onto my scope.  When I unscrew the 2" visual back/ end of the focuser with the three clamping screws I am left with a threaded hole of just over 53mm.  The diagrams of the reducer show it having a 63x1mm thread.  Those dimensions sound like a really large diameter for a focuser on a 61mm apo.  I am hoping that those should say 53x1mm. 

 

Would someone be willing to confirm the size of the focuser opening or the threads on the scope side of the reducer/ flattener?

 

Thank you very much,

Joe



#172 Joe Bruessow

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Posted 05 September 2020 - 01:57 PM

I am hoping those of you who own this scope and reducer/flattener can help me out.  I have a Stellarvue SV60eds (60mm f5.5 fpl53 doublet).  I assumed this was the same exact scope and want to buy the 0.8x reducer/flattener for it. 

 

Unfortunately, when I did some measuring it doesn't look like it will thread onto my scope.  When I unscrew the 2" visual back/ end of the focuser with the three clamping screws I am left with a threaded hole of just over 53mm.  The diagrams of the reducer show it having a 63x1mm thread.  Those dimensions sound like a really large diameter for a focuser on a 61mm apo.  I am hoping that those should say 53x1mm. 

 

Would someone be willing to confirm the size of the focuser opening or the threads on the scope side of the reducer/ flattener?

 

Thank you very much,

Joe

I think I may have solved my own problem.  I think the focuser has changed... The description of the Sharpstar 61edph says that it has a 2.5" focuser... mine must only be a 2" - darn!



#173 gnarayan

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Posted 05 September 2020 - 02:08 PM

I am hoping those of you who own this scope and reducer/flattener can help me out.  I have a Stellarvue SV60eds (60mm f5.5 fpl53 doublet).  I assumed this was the same exact scope and want to buy the 0.8x reducer/flattener for it. 

 

Unfortunately, when I did some measuring it doesn't look like it will thread onto my scope.  When I unscrew the 2" visual back/ end of the focuser with the three clamping screws I am left with a threaded hole of just over 53mm.  The diagrams of the reducer show it having a 63x1mm thread.  Those dimensions sound like a really large diameter for a focuser on a 61mm apo.  I am hoping that those should say 53x1mm. 

 

Would someone be willing to confirm the size of the focuser opening or the threads on the scope side of the reducer/ flattener?

 

Thank you very much,

Joe

It really is an M63 thread - not a typo. Makes it hard to set up a compatible 1x flattener as well - the WO Flat61A is M54.



#174 Joe Bruessow

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Posted 05 September 2020 - 02:15 PM

It really is an M63 thread - not a typo. Makes it hard to set up a compatible 1x flattener as well - the WO Flat61A is M54.

Thanks gnarayan - much appreciated.  I guess I will dump it and go in a new direction.



#175 kel123

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Posted 05 September 2020 - 04:34 PM

Thanks gnarayan - much appreciated. I guess I will dump it and go in a new direction.


What about an adapter?


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