Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Pico-6 and Pico-8 - cutest little maksutovs ever!

  • Please log in to reply
195 replies to this topic

#126 MortonH

MortonH

    Viking 1

  • -----
  • Posts: 831
  • Joined: 12 May 2007
  • Loc: Sydney, Australia

Posted 06 September 2016 - 06:18 PM

First light was not so promising, though. The scope has loads and loads of spherical aberration. So much, that it is basically unusable, even at low magnifications. A 25mm Zeiss eyepiece showed it clearly. In a 14mm ES82, stars were never pinpoint, but small, fuzzy disks. Bright stars had a sharp airy disk, surrounded by very many diffraction rings or a large halo of diffuse light, depending on the focus. There was not a point of best focus, just a range of different sorts of foci. It's the worst star test I've seen in a very long time. 

 

That is a real shame, because it was apparent that if the scope had been sharp, the views would have been staggeringly good for its aperture. Even with the fuzzy optics, I was getting strong hints of beginning resolution of M13 in the 14mm ES82 (64x) and could see NGC 6207 as a small smudge. Deep-sky contrast appeared very good. I did not continue my observations and stopped there.

 

The scope is not mine and now I have the unfortunate job of telling the owner, who so graciously lend it to me, the bad news. I don't know if he has any possibilities of returning it for a refund or another sample, as this was a special low-price sample, due to the interior paint damage.  

 

What a bummer. 

 

 

Clear skies!
Thomas, Denmark

 

The paint damage is no excuse for terrible optics. Sounds to me that it's not fit for purpose and should be taken back by the seller.


Edited by MortonH, 06 September 2016 - 10:13 PM.

  • gfstallin and Joe1950 like this

#127 SkyRemat

SkyRemat

    Sputnik

  • -----
  • Posts: 25
  • Joined: 24 Jul 2012

Posted 07 September 2016 - 04:43 AM

First light was not so promising, though. The scope has loads and loads of spherical aberration. So much, that it is basically unusable, even at low magnifications. A 25mm Zeiss eyepiece showed it clearly. In a 14mm ES82, stars were never pinpoint, but small, fuzzy disks. Bright stars had a sharp airy disk, surrounded by very many diffraction rings or a large halo of diffuse light, depending on the focus. There was not a point of best focus, just a range of different sorts of foci. It's the worst star test I've seen in a very long time. 

 

That is a real shame, because it was apparent that if the scope had been sharp, the views would have been staggeringly good for its aperture. Even with the fuzzy optics, I was getting strong hints of beginning resolution of M13 in the 14mm ES82 (64x) and could see NGC 6207 as a small smudge. Deep-sky contrast appeared very good. I did not continue my observations and stopped there.

 

The scope is not mine and now I have the unfortunate job of telling the owner, who so graciously lend it to me, the bad news. I don't know if he has any possibilities of returning it for a refund or another sample, as this was a special low-price sample, due to the interior paint damage.  

 

What a bummer. 

 

 

Clear skies!
Thomas, Denmark

Did you check collimation ? Or may be a defective one...My Omegon has no spherical aberration that bothers me...interesting



#128 Astrojensen

Astrojensen

    Voyager 1

  • *****
  • topic starter
  • Posts: 11343
  • Joined: 05 Oct 2008
  • Loc: Bornholm, Denmark

Posted 07 September 2016 - 05:08 AM

Collimation was dead on. The scope is certainly defect, with that much spherical aberration. A shame, because the spurious disk of Altair was very crisp, apart from being surrounded by a huge halo of unfocused light, so the polish is superb.

 

 

Clear skies!

Thomas, Denmark



#129 Riccardo_italy

Riccardo_italy

    Viking 1

  • -----
  • Posts: 536
  • Joined: 29 Sep 2014
  • Loc: Italy

Posted 07 September 2016 - 01:55 PM

Maybe the idea is very stupid. Well, probably it is. But....

 

Suppose you want to do AP but you are quite close the mount weight limit and, at the same time, your telescope has quite a long focal lenght. For example, suppose you want to try AP using an HEQ-5 and C8 (with the reducer, of course, but you are still close to the maximum of the mount load for AP).

You need to keep the weight as lower as possible but you struggle because the guiding scope need to have quite a long focal lenght.

 

What about using the Mak 60 (600gr!!) for guiding, mounting it instead of the standard finderscope?

 

Those little maks are, by far, the smallest telescopes with such a long focal lenght. I can't imagine a better combination as a guiding scope.


Edited by Riccardo_italy, 07 September 2016 - 02:00 PM.

  • Bomber Bob, gfstallin and Joe1950 like this

#130 Astrojensen

Astrojensen

    Voyager 1

  • *****
  • topic starter
  • Posts: 11343
  • Joined: 05 Oct 2008
  • Loc: Bornholm, Denmark

Posted 08 September 2016 - 10:16 AM

I think they would work well as long focal length guidescopes. There is basically no mirror flop in the one I have for testing, so guiding should be accurate. I am rather amazed how small and lightweight the Pico-80 is.

 

 

Clear skies!
Thomas, Denmark


  • Bomber Bob and Joe1950 like this

#131 Traveler

Traveler

    Mercury-Atlas

  • *****
  • Posts: 2727
  • Joined: 19 Aug 2007
  • Loc: The Netherlands

Posted 08 September 2016 - 01:40 PM

Thanks Thomas for your nice field test!

One can see that besides form, you have to concern function as well. I mean, the Pico's look (very) good but if your findings are not just for the ones you tested, well then i am not interested anymore.



#132 Astrojensen

Astrojensen

    Voyager 1

  • *****
  • topic starter
  • Posts: 11343
  • Joined: 05 Oct 2008
  • Loc: Bornholm, Denmark

Posted 08 September 2016 - 02:07 PM

Several users in this thread has reported excellent optics in their PICO's. The one I tested is the ONLY bad one mentioned so far in this thread. The only conclusion we can draw from this so far, is that at least one bad sample has slipped through the QC. 

 

 

Clear skies!
Thomas, Denmark



#133 Larry Carlino

Larry Carlino

    Sputnik

  • *****
  • Posts: 32
  • Joined: 05 Jun 2006

Posted 08 September 2016 - 06:35 PM

My Pico 8 also displays very poor optical quality: a LOT of spherical aberration that produces a foggy glare around bright objects.  Not too bad up to about 50x, but 100x shows a washed-out Jupiter, Saturn, and moon.  Very difficult to focus properly as it lacks "snap."  Quite disappointing, with performance far short of the Celestron (Synta) 90mm Mak.

COULD be good, but basically a waste of money.



#134 Astrojensen

Astrojensen

    Voyager 1

  • *****
  • topic starter
  • Posts: 11343
  • Joined: 05 Oct 2008
  • Loc: Bornholm, Denmark

Posted 09 September 2016 - 02:23 AM

That's not good news. Seems like there's a considerable QC problem.

 

 

Clear skies!
Thomas, Denmark



#135 MortonH

MortonH

    Viking 1

  • -----
  • Posts: 831
  • Joined: 12 May 2007
  • Loc: Sydney, Australia

Posted 09 September 2016 - 06:33 AM

From the Kasai website (underline added by me):

 

<Collimation (Optical Axis)>
 

The primary mirror collimation screws are equipped on the tail part (around the eyepiece adapter), permitting fine adjustment of the optical axis. Still, as each unit is carefully tested and precisely collimated by Kasai before shipment, and the scope itself is durable enough to keep well collimated condition under normal usage, generally there will be no need for the users dare to make re-collimation works.

 

 

Something is not right.


Edited by MortonH, 09 September 2016 - 06:53 AM.


#136 gfstallin

gfstallin

    Viking 1

  • *****
  • Posts: 670
  • Joined: 08 Aug 2015
  • Loc: Cheverly, Maryland USA

Posted 10 September 2016 - 03:00 AM

From the Kasai website (underline added by me):

 

<Collimation (Optical Axis)>
 

The primary mirror collimation screws are equipped on the tail part (around the eyepiece adapter), permitting fine adjustment of the optical axis. Still, as each unit is carefully tested and precisely collimated by Kasai before shipment, and the scope itself is durable enough to keep well collimated condition under normal usage, generally there will be no need for the users dare to make re-collimation works.

 

 

Something is not right.

Unless someone boarded the cargo plane and switched out telescopes and labels like some sort of budding optical evil super villain, I'd say the sentence you underlined is what is not right. 


  • MortonH likes this

#137 mclewis1

mclewis1

    Thread Killer

  • *****
  • Posts: 18034
  • Joined: 25 Feb 2006
  • Loc: New Brunswick, Canada

Posted 10 September 2016 - 08:32 AM

That depends on to what standards Kasai tests to. It sounds like coming out of the factory that the optical alignment is very good but a strong  aberration has shown up in some samples. That to me sounds like a very specific issue with the figuring of the optics rather than the mechanicals of the scope itself.



#138 MortonH

MortonH

    Viking 1

  • -----
  • Posts: 831
  • Joined: 12 May 2007
  • Loc: Sydney, Australia

Posted 10 September 2016 - 08:43 AM

That depends on to what standards Kasai tests to. It sounds like coming out of the factory that the optical alignment is very good but a strong  aberration has shown up in some samples. That to me sounds like a very specific issue with the figuring of the optics rather than the mechanicals of the scope itself.

 

Can you "carefully test and precisely collimate" it without noticing such significant SA?



#139 mwedel

mwedel

    Goofing off

  • *****
  • Posts: 1179
  • Joined: 16 Dec 2007
  • Loc: Claremont, CA

Posted 10 September 2016 - 03:16 PM

The claim that EVERY unit is carefully tested before shipping is simply false. As I explained here, my unit arrived with mechanical problems that made it impossible to insert a diagonal or eyepiece, until I fixed the compression ring inside the visual back. It wasn't a matter of the compression ring coming unseated. It was machined wrong, so it wouldn't fit down it its groove. There was no way to get a 1.25" anything in there.

 

So, two possibilities: (1) it was tested with a different, fully functional visual back, which was then taken out and replaced with a defective visual back before it was sent to me. Can't think of any reason why that would happen, and I think that is sufficiently unlikely we can ignore it.

 

Or, (2), at least some of the units are shipping without being tested. That's the most obvious explanation for what happened with my scope, and it would explain the wildly inconsistent results that others are getting with theirs.


  • MortonH likes this

#140 MortonH

MortonH

    Viking 1

  • -----
  • Posts: 831
  • Joined: 12 May 2007
  • Loc: Sydney, Australia

Posted 10 September 2016 - 08:26 PM

I emailed Kasai a link to this thread and asked for comment.  Here's their reply:

 

 

The PICO-8 with severe spherical aberration was among the batch supplied to a dealer in Denmark last year.

I could know this fact because it was said as the interior paint was badly peeled off - It was among the ones sold as “factory second” for half price. (And I believe the end user should have paid half price for it, too.) Concerning those units, it’s true that there were some with poor optical performance.

However, such a defective unit is never supplied as long as it’s sold for regular price.

Also I dare to emphasize the fact that we do perform visual test on each unit with artificial stars - to check the residual aberration, collimation and mirror shift.
Somebody who bought PICO-6 suspected us of this fact, as the brass ring in the eyepiece adapter was bent and it couldn’t accept an eyepiece easily.
I feel sorry we forgot to check this defect on this case, but still this has nothing to do with our visual test.
As mentioned above, we use artificial stars for the visual test, and, to reach the focus, some stacked M42 extension tubes are used. (As you see in our catalog, PICO has M42 threads outside the eyepiece adapter.) As a result, when testing, the original 1.25” eyepiece sleeve is not used.

And, concerning the collimation, of course we adjust each unit to the best collimated condition before shipment.
However, as there are only 3 “push & pull” collimation screws and no “stopper screws” are provided, sometimes (especially when exported) it becomes misaligned because of the rough treatments during the long transport. Still, the user can re-collimate it rather easily - just see a bright star (or artificial stars) in the center of the field and adjust the collimation screws for the defocused star image to be concentric and the focused image to be round with a few uniform diffraction rings

By the way, unfortunately the delivery of PICO-8 is delayed.

They were delivered from the factory late last month, but we found a mechanical problem in every unit - now we are discussing with the factory to solve it.
I never want to supply defective units to our customers. I think this problem can be solved and make shipment within 1-2 months. Thanks for your patience.

A superfluous information:

The same scope is supplied by Omegon, Germany. The basic features are the same as PICO-8, but there is one important difference. Omegon’s has a very thick secondary baffle, and it causes a pretty vignetting on the clear aperture. Concretely speaking, it is not 80mm f/11 but practically 60mm f/15. Of course the star image may become sharper (with smaller aperture and slower f-ratio), but the light gathering power and the resolution are much inferior. To avoid this serious problem, we have asked the factory to remove this evil secondary baffle from every PICO-8, to keep 80mm full clear aperture.


Edited by MortonH, 10 September 2016 - 08:27 PM.

  • Andy Howie, Nadrek, Live_Steam_Mad and 5 others like this

#141 gfstallin

gfstallin

    Viking 1

  • *****
  • Posts: 670
  • Joined: 08 Aug 2015
  • Loc: Cheverly, Maryland USA

Posted 10 September 2016 - 09:25 PM

I emailed Kasai a link to this thread and asked for comment.  Here's their reply:

 

 

The PICO-8 with severe spherical aberration was among the batch supplied to a dealer in Denmark last year.

I could know this fact because it was said as the interior paint was badly peeled off - It was among the ones sold as “factory second” for half price. (And I believe the end user should have paid half price for it, too.) Concerning those units, it’s true that there were some with poor optical performance.

However, such a defective unit is never supplied as long as it’s sold for regular price.

Also I dare to emphasize the fact that we do perform visual test on each unit with artificial stars - to check the residual aberration, collimation and mirror shift.
Somebody who bought PICO-6 suspected us of this fact, as the brass ring in the eyepiece adapter was bent and it couldn’t accept an eyepiece easily.
I feel sorry we forgot to check this defect on this case, but still this has nothing to do with our visual test.
As mentioned above, we use artificial stars for the visual test, and, to reach the focus, some stacked M42 extension tubes are used. (As you see in our catalog, PICO has M42 threads outside the eyepiece adapter.) As a result, when testing, the original 1.25” eyepiece sleeve is not used.

And, concerning the collimation, of course we adjust each unit to the best collimated condition before shipment.
However, as there are only 3 “push & pull” collimation screws and no “stopper screws” are provided, sometimes (especially when exported) it becomes misaligned because of the rough treatments during the long transport. Still, the user can re-collimate it rather easily - just see a bright star (or artificial stars) in the center of the field and adjust the collimation screws for the defocused star image to be concentric and the focused image to be round with a few uniform diffraction rings

By the way, unfortunately the delivery of PICO-8 is delayed.

They were delivered from the factory late last month, but we found a mechanical problem in every unit - now we are discussing with the factory to solve it.
I never want to supply defective units to our customers. I think this problem can be solved and make shipment within 1-2 months. Thanks for your patience.

A superfluous information:

The same scope is supplied by Omegon, Germany. The basic features are the same as PICO-8, but there is one important difference. Omegon’s has a very thick secondary baffle, and it causes a pretty vignetting on the clear aperture. Concretely speaking, it is not 80mm f/11 but practically 60mm f/15. Of course the star image may become sharper (with smaller aperture and slower f-ratio), but the light gathering power and the resolution are much inferior. To avoid this serious problem, we have asked the factory to remove this evil secondary baffle from every PICO-8, to keep 80mm full clear aperture.

Morton, thank you.



#142 Larry Carlino

Larry Carlino

    Sputnik

  • *****
  • Posts: 32
  • Joined: 05 Jun 2006

Posted 11 September 2016 - 08:27 AM

For the record, my optically poor Pico-8 was purchased directly from Kasai at its regular price - no discount and no flaking paint. 

Larry Carlino


  • Live_Steam_Mad likes this

#143 Joe Gerardi

Joe Gerardi

    Viking 1

  • -----
  • Posts: 622
  • Joined: 23 Jul 2016
  • Loc: Savannah, GA, USA

Posted 11 September 2016 - 09:52 AM

What did they say when you contacted them?

 

..Joe



#144 Larry Carlino

Larry Carlino

    Sputnik

  • *****
  • Posts: 32
  • Joined: 05 Jun 2006

Posted 11 September 2016 - 08:27 PM

I sent a description of the defective Pico-8 to Kasai Trading.  Mr. Kasai replied immediately, apologized for the inconvenience, and will send out a replacement as soon as one is available in 1 to 2 months.  Excellent customer service.

Larry C.


  • MortonH, Live_Steam_Mad, Bomber Bob and 1 other like this

#145 Joe Gerardi

Joe Gerardi

    Viking 1

  • -----
  • Posts: 622
  • Joined: 23 Jul 2016
  • Loc: Savannah, GA, USA

Posted 11 September 2016 - 09:21 PM

That's good news!

 

..Joe



#146 emilslomi

emilslomi

    Ranger 4

  • -----
  • Posts: 316
  • Joined: 12 Nov 2015
  • Loc: Alps

Posted 12 September 2016 - 03:40 AM

I bought a Pico-8 some months ago as a retirement present for a friend. I checked it out before I wrapped the present, and it looked good up to 100x with the supplied 9mm eyepiece. Didn't check higher. I had just used my WO before that on the same objects. A tad less contrast and less sharpness, but nothing to complain about given the type and price. It has been received well too. I'll probably get one myself because of the form factor. Communication at the time with Kasai was very pleasant. OK, the RDF is about as cheap as it goes, but usable after all if adjusted fresh each session.

 

Cheers, Emil


  • MortonH, gfstallin and Augustus like this

#147 gfstallin

gfstallin

    Viking 1

  • *****
  • Posts: 670
  • Joined: 08 Aug 2015
  • Loc: Cheverly, Maryland USA

Posted 01 October 2016 - 05:53 AM

Omegon 90mm ‘MightyMak’

 

90mm aperture, 1000mm f/l, f/11.3, 1.3kg OTA weight.

 

 

gallery_249298_5348_25560.jpg

gallery_249298_5348_89478.jpg

How do you like your MightyMak? At 1000mm fl, it provides a slightly wider field than other 90mm Maks on the market. I'm looking for something ultra portable. Maybe this can fit the bill. 

 

George


  • MGD likes this

#148 Shorty Barlow

Shorty Barlow

    Viking 1

  • -----
  • Posts: 659
  • Joined: 15 Sep 2015
  • Loc: Lloegyr

Posted 01 October 2016 - 02:41 PM

 

Omegon 90mm ‘MightyMak’

 

90mm aperture, 1000mm f/l, f/11.3, 1.3kg OTA weight.

 

 

gallery_249298_5348_25560.jpg

gallery_249298_5348_89478.jpg

How do you like your MightyMak? At 1000mm fl, it provides a slightly wider field than other 90mm Maks on the market. I'm looking for something ultra portable. Maybe this can fit the bill. 

 

George

 

It's a nice light little Mak, in fact the focal ratio is f/11.3. After reading some of the posts on this thread though something has occurred to me. I have always had difficulty getting a really sharp focus above about 50-66x magnification. Some have claimed the same thing and I always put it down to conditions and the fact it only has a 90mm aperture. So it may be a collimation problem. In retrospect I wonder if the Synta 90mm Mak's wouldn't have been a better option.


  • gfstallin likes this

#149 gfstallin

gfstallin

    Viking 1

  • *****
  • Posts: 670
  • Joined: 08 Aug 2015
  • Loc: Cheverly, Maryland USA

Posted 01 October 2016 - 09:14 PM

 

 

Omegon 90mm ‘MightyMak’

 

90mm aperture, 1000mm f/l, f/11.3, 1.3kg OTA weight.

 

 

gallery_249298_5348_25560.jpg

gallery_249298_5348_89478.jpg

How do you like your MightyMak? At 1000mm fl, it provides a slightly wider field than other 90mm Maks on the market. I'm looking for something ultra portable. Maybe this can fit the bill. 

 

George

 

It's a nice light little Mak, in fact the focal ratio is f/11.3. After reading some of the posts on this thread though something has occurred to me. I have always had difficulty getting a really sharp focus above about 50-66x magnification. Some have claimed the same thing and I always put it down to conditions and the fact it only has a 90mm aperture. So it may be a collimation problem. In retrospect I wonder if the Synta 90mm Mak's wouldn't have been a better option.

 

Nooo! I was prepared to order it from Astroshop for my fiancee as a wedding gift. She has become obsessed with the idea of attaching her Nikon DSLR to a telescope to use as a telephoto lens. With the C8 and C9.25 as overkill for that purpose, I thought this would have been perfect at 1000mm. The search begins anew...

 

Thanks for the information. 

 

50-66 power is way too low for a breakdown in images for a 90mm. I think you can adjust the collimation on these via screws on the rear cell. 

 

George



#150 Shorty Barlow

Shorty Barlow

    Viking 1

  • -----
  • Posts: 659
  • Joined: 15 Sep 2015
  • Loc: Lloegyr

Posted 02 October 2016 - 01:11 AM

 

 

 

Omegon 90mm ‘MightyMak’

 

90mm aperture, 1000mm f/l, f/11.3, 1.3kg OTA weight.

 

 

gallery_249298_5348_25560.jpg

gallery_249298_5348_89478.jpg

How do you like your MightyMak? At 1000mm fl, it provides a slightly wider field than other 90mm Maks on the market. I'm looking for something ultra portable. Maybe this can fit the bill. 

 

George

 

It's a nice light little Mak, in fact the focal ratio is f/11.3. After reading some of the posts on this thread though something has occurred to me. I have always had difficulty getting a really sharp focus above about 50-66x magnification. Some have claimed the same thing and I always put it down to conditions and the fact it only has a 90mm aperture. So it may be a collimation problem. In retrospect I wonder if the Synta 90mm Mak's wouldn't have been a better option.

 

Nooo! I was prepared to order it from Astroshop for my fiancee as a wedding gift. She has become obsessed with the idea of attaching her Nikon DSLR to a telescope to use as a telephoto lens. With the C8 and C9.25 as overkill for that purpose, I thought this would have been perfect at 1000mm. The search begins anew...

 

Thanks for the information. 

 

50-66 power is way too low for a breakdown in images for a 90mm. I think you can adjust the collimation on these via screws on the rear cell. 

 

George

 

You're welcome. Yeah, I nearly bought an Orion (Synta) 90mm instead of the 90mm MightyMak, I think it would have been better for high magnification. I'll have to take a look at the collimation on the Omegon one day. Meanwhile I've bought a Sky-Watcher ST80.


Edited by Shorty Barlow, 02 October 2016 - 01:12 AM.



CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics