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

"Black Friday" Classic Astro-Physics 6" f/8

  • Please log in to reply
81 replies to this topic

#1 jragsdale

jragsdale

    Skylab

  • *****
  • topic starter
  • Posts: 4,174
  • Joined: 07 Dec 2015
  • Loc: Idaho

Posted 05 December 2024 - 08:32 PM

As alluded to in the Classifieds thread, I was the lucky buyer of the "Black Friday" Astro-Physics 6" f/8 that was listed on Astromart for $1200. Plus an extra $100 for shipping and it's now in my possession! I've always wanted an AP scope but could never bring myself to jump at the astronomical prices they usually garner. I'm a creature of habit and my interests usually favor the underdog, the cheap and dirty fix-er-upper type things. This was right up my alley, checking both boxes in spades! And I've wanted a classic 1980s version because I'm a classic nut at heart as well.

 

Nicely packed and shipped in a lined wooden case. The scope arrived without any shipping damage. The dew shield is pretty bent as shown on the listing, I was expecting that. First thing I checked was the lens, it's got some dust and dew residue on both sides, I'll be cleaning this once I get to it. Coatings look to be in good shape. The set screws to remove the lens cell were rusted and stuck, I had a hard time getting them out but after I applied my 50/50 solution of Acetone/ATF, they came out with a little encouragement. I'll replace these with new stainless versions. Here's the lens in cell once removed from the tube:

 

20241205_115937.jpg

 

Writing marks on the edge of the lens as seen through the front (and reversed in post to make them readable):

 

20241205_104835-COLLAGE.jpg

 

The tube is dent free, but looks to have been repainted sometime in the past. There's some overspray on parts, and the texture is very inconsistent, the top of the tube feels like sandpaper and the bottom feels smooth. I will definitely be stripping and repainting, most likely powder coating for long term durability. AP says most likely "Corvette White".

 

Nice Losmandy dovetail and (I believe) Parallax rings, they were quite dirty, needed a full disassemble, scrub with soapy hot water and brush, here they are after cleaning:

 

20241205_103549.jpg

 

The focuser arrived with a slight tilt, which I thought was odd: 

 

20241205_111416.jpg

 

There are 3 equally spaced radial holes in the tube, but no screws attached. There are 2 bolts that are about 1" apart from each other that apparently hold the focuser on the tube, which obviously won't prevent tilt if the opposite side gets bumped. I took these off to pull the focuser and see the flange and that's when I noticed that the 3 radial holes are only partially drilled, what look like little more than pilot holes, maybe 1mm deep with no threads:

 

20241205_112125.jpg

 

How can it be that AP shipped a scope/focuser without the holes actually drilled to hold it on? So odd! Luckily the 2 holes that do mount (which look spaced apart for a finderscope bracket) do a pretty good job as long as the focuser is banged in square to the tube, letting tension do most of the work. And they line up with all the pilots holes and the holes in the tube, so all I need to do is finish drilling the holes in the focuser flange and tap them and I'll be in business. I'll probably enlarge the tube holes too to give a small wiggle room for squaring the focuser to the lens once it's put back together.

 

Here's all the parts, it's a great scope optically I'm sure, but I definitely want to refurb/improve this scope so it's back to shiny and new cosmetically as well.

 

20241205_123757.jpg

 

So, is it still a great deal? To me it is! I don't mind cleaning, drilling, painting, tweaking to get things back up to optimal, but I know to others, they might be in over their head or disappointed in the amount of work it needed. At the end of the day, the lens (what counts) is great and this will be a phenomenal performer! I'm grateful for the opportunity to own such a legendary classic scope.

 

*UPDATE* : ccwemyss correctly pointed out that this originally had set screws in the tube to hold the focuser, which weren't on my scope and the ATM paint job had filled the threads so I missed that part.


Edited by jragsdale, 05 December 2024 - 10:01 PM.

  • Steve_M_M, Paul Hyndman, deSitter and 24 others like this

#2 edsmx5

edsmx5

    Vanguard

  • *****
  • Posts: 2,031
  • Joined: 09 Feb 2023
  • Loc: Lower Pottsgrove, Pa. Bortle 5+

Posted 05 December 2024 - 08:44 PM

Nice work, good luck with the lens cleaning, be sure to post an update, thanks
  • jragsdale likes this

#3 J A VOLK

J A VOLK

    Surveyor 1

  • *****
  • Posts: 1,543
  • Joined: 24 May 2006
  • Loc: Flagstaff

Posted 05 December 2024 - 08:50 PM

Well you are the right person to get it back in shape!  Those lenses were very well figured.   Not an APO by modern standards, but reasonable.  Hopefully it is in collimation when you get it put together, as not a collimatible cell, but you are capable of adjusting if needed.  I think it is a very good deal in the right hands.


  • Steve_M_M and jragsdale like this

#4 jragsdale

jragsdale

    Skylab

  • *****
  • topic starter
  • Posts: 4,174
  • Joined: 07 Dec 2015
  • Loc: Idaho

Posted 05 December 2024 - 09:00 PM

Not an APO by modern standards, but reasonable.  Hopefully it is in collimation when you get it put together, as not a collimatible cell, but you are capable of adjusting if needed.

The seller was generous enough to throw in a 2" Baader Fringe Killer filter as well, so I'll be ready for visual use, and if I use it for deep sky imaging, I use a mono camera and filters anyways so CA will not be an issue, each filter is focused for the target end of the spectrum.

 

And yes, I've worked with a few scopes where "collimation", if you could call it that, is accomplished by just loosening the focuser and lens cell and tilting them to the where they look best and locking them down at that spot. I assume AP got them pretty square though so it shouldn't need much adjustment.


  • Defenderslideguitar likes this

#5 ccwemyss

ccwemyss

    Gemini

  • *****
  • Posts: 3,326
  • Joined: 11 Aug 2016
  • Loc: Massachusetts

Posted 05 December 2024 - 09:17 PM

That's about 18 months later than my 6" f9. The cell is the same as a Jaegers 6". The tube is Hastings pipe. The holes in the tube are threaded for 6/32 set screws, and they just press against divots in the cell and the focuser. The other two screws are indeed for a finder. They sold it with a UO 8x50 right-angle finder from NS, painted white. I'd be curious to know if they were still using the single baffle casting, with a 3" hole, half-way up the tube. I redid mine with a 6-way baffle system that improved contrast, and also enlarged the fully illuminated field. I eventually replaced the focuser too, and that version is now on the Jaegers 6" f5 that you sold to me. (In 1985, they actually shipped them with a temporary focuser that was just a Jaegers 2" with a flange to fit the tube.)

 

The Parallax rings are a big improvement over the original, non-hinged ones. Congratulations on a great find!

 

There might be some coating loss. The coatings they used in this era were not stable. Despite being stored indoors for its entire life and never being touched, mine started showing loss a few years ago, and I had to send it back to AP, where Roland polished the coating off. He gave it such a high polish that you'd easily think it was still coated. They replaced the oil at the same time. 

 

It does look repainted, but don't entirely blame the prior owner. AP did a lousy job painting these. Mine is rough and uneven too. I keep thinking I'll take it apart again and give it a nicer finish. I'm not sure if I'll do the original Corvette White, since I don't know if the powder coater can match it, or just go with a rattle can that's close. I've never used the not-so-local but nearest coater, so I'm not sure I'd trust them with this as a first job.

 

Don't apologize for the amount of work you're going to put into it. The original wasn't a work of art like their later scopes. As you say, it was all about the objective, and the rest of the scope was essentially an ATM build they threw together for the convenience of customers who lacked the DIY skills. I'm sure you'll make it much better than original. 

 

It's nice to see that he was still signing them at that point. When I ordered mine in '84, I asked him to please sign the objective, since I believed he would eventually be as legendary as Clark. I don't know if he was already planning to do that anyway, but maybe I at least encouraged him to follow through. 

 

Chip W. 


  • BillinBallard, k5apl, CharLakeAstro and 3 others like this

#6 starman876

starman876

    Nihon Seiko

  • *****
  • Vendors
  • Posts: 26,719
  • Joined: 28 Apr 2008
  • Loc: VA

Posted 05 December 2024 - 09:28 PM

If I remember correctly on the 6" F8 I used to have that the allen screws are set screws and the holes are not tapped.  I know it sounds strange, but that  is how it was built. 



#7 jragsdale

jragsdale

    Skylab

  • *****
  • topic starter
  • Posts: 4,174
  • Joined: 07 Dec 2015
  • Loc: Idaho

Posted 05 December 2024 - 09:51 PM

The cell is the same as a Jaegers 6". The tube is Hastings pipe. The holes in the tube are threaded for 6/32 set screws, and they just press against divots in the cell and the focuser. The other two screws are indeed for a finder. They sold it with a UO 8x50 right-angle finder from NS, painted white. I'd be curious to know if they were still using the single baffle casting, with a 3" hole, half-way up the tube.

You're right! The focuser holes on the tube had filled with paint from the previous paint job so they didn't look threaded. I never would think set screws could be done in such a thin tube! I ran a 6-32 tap into the holes gently by hand and they chewed out the paint and revealed the metal threads. That makes sense now! I'll still go with my original plan though as set screws with threaded tube and divots in the flange means zero adjustment possibilities for final squaring to the tube. 

 

20241205_194004.jpg

 

And yes, this one has a single baffle halfway in the tube. Do you have any photos of how you made yours?

 

20241205_194226.jpg


Edited by jragsdale, 05 December 2024 - 09:52 PM.

  • Defenderslideguitar likes this

#8 jragsdale

jragsdale

    Skylab

  • *****
  • topic starter
  • Posts: 4,174
  • Joined: 07 Dec 2015
  • Loc: Idaho

Posted 05 December 2024 - 11:21 PM

Nice work, good luck with the lens cleaning, be sure to post an update, thanks

I followed the instructions on Astro-Physics website for cleaning both sides and it turned out great!

 

https://astro-physic...ing-formula.pdf

 

A few very minor sleeks visible only at certain angles but otherwise excellent!

Attached Thumbnails

  • 20241205_205753.jpg
  • 20241205_205652.jpg

Edited by jragsdale, 05 December 2024 - 11:22 PM.

  • Paul Hyndman, deSitter, photiost and 17 others like this

#9 edsmx5

edsmx5

    Vanguard

  • *****
  • Posts: 2,031
  • Joined: 09 Feb 2023
  • Loc: Lower Pottsgrove, Pa. Bortle 5+

Posted 06 December 2024 - 02:48 AM

I followed the instructions on Astro-Physics website for cleaning both sides and it turned out great!

https://astro-physic...ing-formula.pdf

A few very minor sleeks visible only at certain angles but otherwise excellent!



Nicely done!
  • k5apl and jragsdale like this

#10 jragsdale

jragsdale

    Skylab

  • *****
  • topic starter
  • Posts: 4,174
  • Joined: 07 Dec 2015
  • Loc: Idaho

Posted 06 December 2024 - 03:32 AM

None of my existing finder brackets matched the existing holes on the tube, the spacing was a little wider than most, so I custom designed one with an exact radius curve (7" OD tube) that works with the existing screws and 3D printed it. 45 minutes later and now I can mount a finderscope!

Attached Thumbnails

  • 20241206_005536.jpg
  • 20241206_005532.jpg

  • Paul Hyndman, clamchip, Bomber Bob and 3 others like this

#11 Weisswurst Josef

Weisswurst Josef

    Ranger 4

  • -----
  • Posts: 370
  • Joined: 22 Feb 2023
  • Loc: Bayern

Posted 06 December 2024 - 03:38 AM

What a great find! Congratulations!

Absolutely in the right hands.

Fine job you did!



#12 ccwemyss

ccwemyss

    Gemini

  • *****
  • Posts: 3,326
  • Joined: 11 Aug 2016
  • Loc: Massachusetts

Posted 06 December 2024 - 07:02 AM

Here's how I designed the new baffles. 

 

AP 6 - 1.jpeg

 

I used the original baffle as an anchor at the back, with aluminum all-thread struts, and cut the other five baffles out of thin aluminum sheet. Pretty tedious running the black nylon nuts to the proper positions, but it provided for very fine adjustment, is very light, and nothing to rust. I used a router with a 45 degree edging bit to angle the hole in the original baffle so it also has a knife edge.

 

Here's how it looks installed, with a 65 watt flood light pointed straight down the tube. Everything is painted with Black 2.0 from Culture Hustle. 

 

AP 6 - 1 (3).jpeg

 

And with just normal room light.

 

AP 6 - 1 (2).jpeg

 

It's very dark in there. Much darker than chalkboard paint. 

 

Chip W. 


  • R Botero, RichA, Bomber Bob and 5 others like this

#13 R Botero

R Botero

    Fly Me to the Moon

  • -----
  • Posts: 6,006
  • Joined: 02 Jan 2009
  • Loc: Kent, England

Posted 06 December 2024 - 07:44 AM

I followed the instructions on Astro-Physics website for cleaning both sides and it turned out great!

 

https://astro-physic...ing-formula.pdf

 

A few very minor sleeks visible only at certain angles but otherwise excellent!

Looks new!  Congratulations and enjoy it!   When I got my 1992 6" f/7.5 StarFire EDF, one of the things I enjoyed the most (besides looking through it) was refurbishing fully with the help of Astro-Physics.  They provided me with colour codes for the paint, I bought a new 4" focuser from them and they even had the replacement decals for the dew shield!  Talk about customer support :waytogo:

 

Roberto


  • jragsdale, Defenderslideguitar and Weisswurst Josef like this

#14 jragsdale

jragsdale

    Skylab

  • *****
  • topic starter
  • Posts: 4,174
  • Joined: 07 Dec 2015
  • Loc: Idaho

Posted 06 December 2024 - 09:54 AM

Looks new!  Congratulations and enjoy it!   When I got my 1992 6" f/7.5 StarFire EDF, one of the things I enjoyed the most (besides looking through it) was refurbishing fully with the help of Astro-Physics.  They provided me with colour codes for the paint, I bought a new 4" focuser from them and they even had the replacement decals for the dew shield!  Talk about customer support waytogo.gif

 

Roberto

Good idea on the decals, I'll definitely ask about those. They are seeing if they have any leftover dew shields from this era as well otherwise I'll probably 3D print a better replacement.

 

I 3D printed a nice ergonomic handle in PETG-CF that will "handle" (:rimshot:) the scope nicely for carrying around.

Attached Thumbnails

  • 20241206_074822.jpg
  • 20241206_074838.jpg

  • R Botero and Bomber Bob like this

#15 jragsdale

jragsdale

    Skylab

  • *****
  • topic starter
  • Posts: 4,174
  • Joined: 07 Dec 2015
  • Loc: Idaho

Posted 06 December 2024 - 12:08 PM

Finished cleaning up everything and replaced all the old rusted fasteners with new stainless. Still plan to repaint down the line but I can't resist getting some views on this beforehand. I checked the focuser and lens cell when completely flush to the tube and they were indeed square and collimated so no changes needed at this time.

 

Tube needed a soft scrub brush and plenty of magic eraser to get it looking pretty good again.

Attached Thumbnails

  • 20241206_094236.jpg
  • 20241206_094139.jpg
  • 20241206_094250.jpg

  • Paul Hyndman, deSitter, payner and 13 others like this

#16 deSitter

deSitter

    Still in Old School

  • *****
  • Posts: 21,316
  • Joined: 09 Dec 2004

Posted 06 December 2024 - 12:26 PM

Finished cleaning up everything and replaced all the old rusted fasteners with new stainless. Still plan to repaint down the line but I can't resist getting some views on this beforehand. I checked the focuser and lens cell when completely flush to the tube and they were indeed square and collimated so no changes needed at this time.

 

Tube needed a soft scrub brush and plenty of magic eraser to get it looking pretty good again.

I found that cerium oxide slurry can really gloss up paint, and fast. Way faster than e.g. Turtle Wax. You may avoid powder coating. Also, I have a finder bracket in use that would work. It has 4 slots. I think this is it.

 

https://www.amazon.c...d=3MMDKB46NTAJL

 

-drl


  • jragsdale likes this

#17 jragsdale

jragsdale

    Skylab

  • *****
  • topic starter
  • Posts: 4,174
  • Joined: 07 Dec 2015
  • Loc: Idaho

Posted 06 December 2024 - 12:47 PM

I found that cerium oxide slurry can really gloss up paint, and fast. Way faster than e.g. Turtle Wax. You may avoid powder coating. Also, I have a finder bracket in use that would work. It has 4 slots. I think this is it.

I'll check that out. I'm not sure if I want to repaint white or vinyl wrap it in something fun, so it's temporary. I have the same bracket in my pile and the screws were even wider than that one allowed. The 3D printed one is plenty strong though, I'm good with it, thanks for checking.



#18 TG

TG

    Gemini

  • *****
  • Posts: 3,310
  • Joined: 02 Nov 2006
  • Loc: Latitude 47

Posted 06 December 2024 - 01:00 PM

What a great find! I don't believe these objectives were coma corrected so alignment of objective and focuser is going to be important.
  • jragsdale likes this

#19 deSitter

deSitter

    Still in Old School

  • *****
  • Posts: 21,316
  • Joined: 09 Dec 2004

Posted 06 December 2024 - 01:28 PM

I'll check that out. I'm not sure if I want to repaint white or vinyl wrap it in something fun, so it's temporary. I have the same bracket in my pile and the screws were even wider than that one allowed. The 3D printed one is plenty strong though, I'm good with it, thanks for checking.

Shootout with a 6" f/8 Newtonian! :)

 

-drl



#20 jragsdale

jragsdale

    Skylab

  • *****
  • topic starter
  • Posts: 4,174
  • Joined: 07 Dec 2015
  • Loc: Idaho

Posted 06 December 2024 - 01:50 PM

What a great find! I don't believe these objectives were coma corrected so alignment of objective and focuser is going to be important.

Yeah, I made sure a [collimated] laser collimator put the dot through the absolute center of the objective and that the reflection of a Cheshire was centered in the reflection of the lens when looking through it. Seems all in order for good high power views.


  • deSitter and TG like this

#21 Don W

Don W

    658th Member

  • *****
  • Moderators
  • Posts: 25,643
  • Joined: 19 May 2003
  • Loc: Cottonwood, Arizona

Posted 06 December 2024 - 02:03 PM

Brings back fond memories. In the mid nineties I had one of those. My first AP. Had the original AP mount too. 
 

Built a massive birch tripod to carry it. 
 

I have had and now have a number of more modern Apos but my favorite is another Christen design, the Brandon 94. It’s my most used scope these days.

 

Enjoy your journey and keep us posted.

 

DonW


  • jragsdale, Defenderslideguitar and Esso2112 like this

#22 ccwemyss

ccwemyss

    Gemini

  • *****
  • Posts: 3,326
  • Joined: 11 Aug 2016
  • Loc: Massachusetts

Posted 06 December 2024 - 02:15 PM

Very nice! Looks like the dew shield straightened up reasonably well. 

 

Hope you get some clear skies to try it out soon.

 

Chip W. 


  • jragsdale likes this

#23 starman876

starman876

    Nihon Seiko

  • *****
  • Vendors
  • Posts: 26,719
  • Joined: 28 Apr 2008
  • Loc: VA

Posted 06 December 2024 - 02:17 PM

The one I had provided awesome views.  Was sad to sell it, but as old age creeps in there are a lot of things one has to give up.  You would think that for a triplet of its age it would easily be bested by modern APO's.  However, that is not the case.   In DPAC the Christian triplet bested many of the imported modern APO doublets.   Did not have a chance to compare it to a modern imported triplet


  • deSitter, jragsdale and Defenderslideguitar like this

#24 deSitter

deSitter

    Still in Old School

  • *****
  • Posts: 21,316
  • Joined: 09 Dec 2004

Posted 06 December 2024 - 02:23 PM

The one I had provided awesome views.  Was sad to sell it, but as old age creeps in there are a lot of things one has to give up.  You would think that for a triplet of its age it would easily be bested by modern APO's.  However, that is not the case.   In DPAC the Christian triplet bested many of the imported modern APO doublets.   Did not have a chance to compare it to a modern imported triplet

RC stressed that mastering spherochromaticism was his goal - I think I have that right. He had to explain why star tests would appear different on either side of focus. The best color correction was a balance between spherochromaticism - change of spherical correction per wavelength - and CA. What mattered was in focus. Maximize the energy in the Airy disk. Color correction was not just a formula.

 

-drl


  • CharLakeAstro and jragsdale like this

#25 jragsdale

jragsdale

    Skylab

  • *****
  • topic starter
  • Posts: 4,174
  • Joined: 07 Dec 2015
  • Loc: Idaho

Posted 06 December 2024 - 02:39 PM

Shootout with a 6" f/8 Newtonian! smile.gif

I could do a fair 6" shootout with what I have on hand right now:

 

Parks 6" f/6 Newtonian

Orion 6" f/12 Maksutov

Jaegers 6" f/15 Achromat


Edited by jragsdale, 06 December 2024 - 03:40 PM.

  • Don W, deSitter and Bonco2 like this


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