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Post a Picture of Your Classic Telescope- with or without you!

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#3751 Rustler46

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Posted 24 October 2020 - 04:57 PM

Nice!!!!! Russ, please start a new topic and tell us about "I was doing photoelectric photometry of variable stars (another story)". I'd be interested in that.

Hi jcruise64,

 

I'll do so, when I get a bit of time. I believe there is an Observational Astrophysics Forum on Cloudy Nights. Perhaps there would be the best place. Just as a teaser, I used a photon-counting photometer. There might be 250 counts in a 10-second integration for the dark measurement (telescope lens cap on). Measuring the variable might have 250,000 counts in ten seconds. The vast majority of these counts were from individual photons - thus the name.

 

Things have gotten much easier since 1985, when I was doing photometry. Check out the December 2020 issue of Sky and Telescope, which has a nice article about using digital cameras to count photons for stellar photometry. See page 60 for DIY Photometry, Measuring Starlight (Backyard Science column - "Measuring the Stars"). If you don't have a paper subscription, I believe you can get a digital (on-line) subscription.   You can really see the focus on science being brought to the fore by Sky and Telescope's new owner, the American Astronomical Society.

 

The article is very interesting, particularly for myself having done that sort of science years ago. It gives the opportunity to contribute data used by professional astronomers. I was privileged to do so for a few years. These scientists would kindly include my name in the  list co-authors for their published papers.

 

Best Regards,

Russ


Edited by Rustler46, 24 October 2020 - 06:47 PM.

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#3752 Rustler46

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Posted 25 October 2020 - 12:08 AM

Got the laser attached to the finder on the 8-inch reflector. Just a single large wire-tie and sculpted piece of wood to hold the laser reasonably parallel to the optical axis. With something like a 5° FOV just seeing the star patterns near where the 8-incher is pointed should suffice for finding DSOs. I enjoy that this finder is RACI, so that mental gymnastics aren't required to match eyepiece view to star atlas.

 

As for the mount, the two heavy pieces of aluminum C-channel are formerly part of a log truck bumper. A local machinist turned that into something adjustable to hold the polar axis bearings. I made the sheet metal cover for the Mathis worm-gear set. The Hurst synchronous motor has died, but could be easily replaced.

 

The photometer is also long gone. But the mount can be drug out of storage and reassembled. I should remove the 8-inch mirror and give it a cleaning before collimation. This may end up being one of my grab-n-go telescopes. While I love my Losmandy mounted C-11 with AT115EDT refractor riding on top, it does take a while to set up and tear down. The mount for my old 8-incher can be left outside under cover in my garden observing site. Then grab the OTA and bolt it on - ready to in less that 2 minutes. We are getting a small bit of much needed drought relief this weekend. But tomorrow night looks to be clear. My old telescope friend will be put back into use. I call it my 8-inch RFT, which stands for Rich Field Telescope. With sub-f/5 optics and 1-1/4 inch eyepieces this gave a wide field of view (wide for the mid 1900s) for DSOs and variable star work. 

Here's another view of the 8-inch photometer rig in the early 1980s..

 

 - 2.jpg

Notice between the counterweight and center pillar the dark home made 1000-volt DC power supply. This supplies 100 volts for each of the 10 stages of the photomultiplier tube in the photometer head. The voltage is fed to the photometer by one of the coax cables. The other carries the measurement signal.

 

Now fast-forward to 2020.  I've gotten all the parts of the mount out of storage, attached laser to finder and will attach telescope to mount to look at tonight's moon. So here is 2020 iteration of my 55-year old equatorial mount. Nothing but the best junk and hardware went into this one.

 

EQ Mount -2.jpg

The cold-rolled steel counterweight shaft is replaced on that end with 1-1/4 inch galvanized water pipe. Added to the crankshaft pulley counterweight is a rust colored handle to some sort of valve. The legs are made of the same pipe and stabilized with small gauge chain under tension.

 

 8-inch RFT - 2.jpg

 

My 8-inch RFT ready to attach to the mount. Note the laser attached to the M-17 finder. With the back fiberglass tube, you can see I favor that color over the more common white to reduce the amount of ambient light reflected toward my face while at the eyepiece.

 

So out it goes onto the mount. This should be interesting with all the dust and spider webs on the primary mirror. But the laser does help pointing the telescope. Along with a star atlas, it's a poor man's go-to rig. I went full retro and used my first original eyepiece - a Brandon 32mm of proprietary optical design. Wow - it takes in the entire Pleiades - at least the entire little dipper figure of bright stars.

 

Changed over to a war surplus 32mm Erfle adapted from over 2-inch to 1-1/4 inch with a brass fitting. This gives a very nice view, slightly larger than the 32 mm Brandon. It is subject of reflections from bright stars just outside the FOV. The field stop is the inside diameter of thin-walled brass tubing. With that eyepiece, the Double Cluster was quite nice. Also stumbled on to the Owl or ET Cluster (NGC 457) - also quite spectacular with its two different colored bright eyes. 

 

This was just a quick reassembly of a telescope that was finished around 1967. The mount attained its present state 15 years later. But I'll be sure to use this grab-n-go telescope more often. And I'll be cleaning the primary mirror, which will help a lot.

 

All the Best,

Russ


Edited by Rustler46, 25 October 2020 - 01:07 AM.

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#3753 John Rogers

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Posted 25 October 2020 - 09:30 AM

Thanks Russ.  I love the old ATMs and am impressed that you have taken the responsibility to preserve it in an operational state.  Do you have the specs for the Hurst motor?  I will see if I can locate and provide one for you.



#3754 Rustler46

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Posted 26 October 2020 - 02:25 AM

Nice!!!!! Russ, please start a new topic and tell us about "I was doing photoelectric photometry of variable stars (another story)". I'd be interested in that.

I've just posted Photoelectric Photometry of Stars - Past and Present in Observational Astrophysics. I hope you enjoy my ramblings.

 

Russ


Edited by Rustler46, 26 October 2020 - 02:27 AM.

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#3755 Rustler46

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Posted 26 October 2020 - 03:21 AM

Thanks Russ.  I love the old ATMs and am impressed that you have taken the responsibility to preserve it in an operational state.  Do you have the specs for the Hurst motor?  I will see if I can locate and provide one for you.

Thanks for your comment and offer, John. The motor has been removed and is in storage on the "astronomy shelf" in the garage. I haven't tested it. But it didn't work last time I plugged it in. Seems strange that an AC synchronous motor would die. But if need be I'm sure I can get a replacement. Do you have a good source?

 

Best Regards,

Russ



#3756 John Rogers

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Posted 26 October 2020 - 09:27 AM

I don't have a source Russ, but I think it would be a worthy cause to see it working again.  I have seen them occasionally offered on eBay etc, but have otherwise not paid much attention.

 

It could be that some oxidation has formed on the gear surfaces causing it to stick and there is not enough torque to get it going.  Perhaps, a gentle back and forth rotation of the spur gear might free it up.

 

 

Regards,

 

 

John



#3757 steve t

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Posted 26 October 2020 - 10:45 AM

I've just posted Photoelectric Photometry of Stars - Past and Present in Observational Astrophysics. I hope you enjoy my ramblings.

 

Russ

Nice writeup, thanks for sharing.



#3758 Rustler46

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Posted 26 October 2020 - 02:27 PM

I don't have a source Russ, but I think it would be a worthy cause to see it working again.  I have seen them occasionally offered on eBay etc, but have otherwise not paid much attention.

 

It could be that some oxidation has formed on the gear surfaces causing it to stick and there is not enough torque to get it going.  Perhaps, a gentle back and forth rotation of the spur gear might free it up.

 

I will be seeing what can be done to get it going as constructed. One interesting point involves the work done by a machinist to fashion the mount. He did a great job on machining as well as the heli-arc work. Also the installation of the worm and worm-gear set was quite well done. It was worth the cost to have an expert do those tasks. But he did did make one understandable error. I gave him the gears supplied with the worm for turning it at the correct rate. To make the drive motor fit under the upper plate next to the worm block, it had to be tucked and connected via a small chain and sprocket. These parts the machinist supplied.

 

I lived in a rural area, about 100 miles away from the machinist's location in Eureka, California. Testing the new equatorial mount, I found that it didn't track correctly. Then I discovered the error. The chain-drive ratio was not the same as that of the gears being replaced. When I contacted the machinist about the problem, he said that the correct sprockets weren't in stock. So he substituted something close. He just didn't understand that the exact gear ratio mattered. Since he was a a full day's round trip away, I never got the problem corrected. The tracking rate was close enough for visual use. And I never did photography with that telescope.

 

So when I complete the resurrection of the mount, I'll have a local machinist provide the correct sprockets for me. Even without a driving motor, the mount is very smooth in use. The clutch on the worm-gear face provides a very nice variable friction - much better than a rolled up wad of newspapers.

 

Another needed addition is to supply a reticle light for the finder. During the war it originally had a small incandescent bulb to illuminate the cross hairs. But a small LED seems appropriate for my use.

 

Warm Regards,

Russ


Edited by Rustler46, 26 October 2020 - 07:09 PM.

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#3759 clamchip

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Posted 26 October 2020 - 04:33 PM

My new 1961 Edmund Deluxe Space Conqueror.

It's still under restoration but now usable.

4-1/4 inch f/10. Edmund has had this scope in their line-up since the mid 1950's and it

remained in continuous production well into the 1970's. 

Originally called the Palomar Jr., everyone called it the Pal Jr.

When the tube went from black to white in the early 60's the name changed. 

With a good diagonal mirror this 4-1/4" spherical system is 1/8th wave or better.

Truly a excellent delightful to use instrument.

Robert

 

IMG_0241.jpg


Edited by clamchip, 26 October 2020 - 04:36 PM.

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#3760 Terra Nova

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Posted 26 October 2020 - 05:13 PM

Very cool Robert! I had one. Mine was a transitional red one. It was cool but it didn’t get a lot of use. When I decided to seriously pare things down I gave it away to a young family that couldn’t afford a telescope and wanted to start a family hobby.

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#3761 Rustler46

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Posted 27 October 2020 - 02:29 AM

I don't have a source Russ, but I think it would be a worthy cause to see it working again.  I have seen them occasionally offered on eBay etc, but have otherwise not paid much attention.

 

It could be that some oxidation has formed on the gear surfaces causing it to stick and there is not enough torque to get it going.  Perhaps, a gentle back and forth rotation of the spur gear might free it up.

John, this evening I made an encouraging discovery. The synchronous motor is not dead, but just has a gummed up gear train as you suggested. I plugged it in, and heard a faint hum. So I gave the output chain sprocket some help and it began to turn, albeit in a labored manner. So I gave it squirt of spray silicone lubricant and will let it sit overnight. Perhaps that will un-gum that old gear train.

 

Edit:
I brought the motor-gearbox assembly indoors to warm up. It runs much smoother now, particularly after sitting the the sun at a window shelf. It sounds like its old self, with kind of a rapid clicking sound. A few years ago when I plugged it in, that sound was missing. So I assumed the motor was dead. I'm pleased it was not. I'm letting it run in that warm environment to get it all un-gummed and turning at its designed rate.

 

Here are a couple of photos of the motor drive assembly:

 

EQ Mount-02377.jpg

 

EQ Mount-02376.jpg

While the chain looks quite robust in this photo, it is actually about 1/8 inch in width, with corresponding small pitch. I'll give it a lube with some bicycle chain spray. This view shows the high quality machining done with scraps left over from that old aluminum log truck bumper.

 

EQ Mount-02378.jpg

This Hurst motor has clockwise or ccw rotation depending on how it is wired. It provides 1/2 RPM at the output shaft. The capacitor shown in the diagram is external, supplied by the user. The 6-inch Mathis worm gear set came with this motor and appropriate spur gear pair. But due to space considerations, I opted for a chain drive.

 

EQ Mount-02381.jpg

This shows where the synchronous motor assembly would attach to drive the worm. Also seen is the babbit declination bearing housing, attachment fitting for the water-pipe counterweight shaft and the flange where the OTA attaches. This flange is just held onto the solid declination shaft by three tiny set screws. This works quite well, if these sets are occasionally snugged up. Friction for the declination movement is provided by small plugs of leather inserted under the two Allen head cap screws that are visible. These are tightened to get the desired amount of resistance.

 

Now I just need to acquire the right chain sprockets for the correct drive speed, and this mount will be good to go. No doubt these can be acquired online. I'll likely just go to a local machinist I know. He would know the correct chain gauge for the sprockets to match the chain I already have. He really does heavy duty machine work. But I'm sure he wouldn't mind a bit of light-duty business. Also it will be fun to converse with him again, since he is an amateur astronomer as well. No doubt a chain drive adds another component to the periodic error of the worm gear set. But since it is only used visually (not photographically), that is really of little consequence.

 

Needless to say this heavy duty GEM has a considerable weight capacity, at least for visual use. While it would no doubt easily carry the OTA of my 10-inch Dob, I'll just continue using it with my home made 8-inch reflector. I have decided to bring all of this information about my home made equatorial mount over into the Equipment > Mounts forum. The 8-inch telescope seems at home here. But much discussion of the mount best resides elsewhere.

 

Warm Regards,

Russ


Edited by Rustler46, 27 October 2020 - 06:26 PM.

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#3762 steve t

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Posted 27 October 2020 - 09:17 AM

Russ,

Very nice setup. 



#3763 clamchip

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Posted 30 October 2020 - 06:38 PM

post-50896-0-33257200-1508032358.jpg


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#3764 CCD-Freak

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Posted 30 October 2020 - 07:25 PM

Oh Nooooo!!!!!.....It is spreading.......grin.gif

 

C8 on Ultima-11-Halloween.jpg

 

 

John Love

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WD5IKX


Edited by CCD-Freak, 30 October 2020 - 07:28 PM.

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#3765 Rustler46

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Posted 30 October 2020 - 08:09 PM

Russ,

Very nice setup. 

Thanks Steve. It's been with me and my home made 'scopes for a long time.


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#3766 John Rogers

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Posted 31 October 2020 - 09:20 AM

John, this evening I made an encouraging discovery. The synchronous motor is not dead, but just has a gummed up gear train as you suggested. I plugged it in, and heard a faint hum. So I gave the output chain sprocket some help and it began to turn, albeit in a labored manner. So I gave it squirt of spray silicone lubricant and will let it sit overnight. Perhaps that will un-gum that old gear train.

 

Edit:
I brought the motor-gearbox assembly indoors to warm up. It runs much smoother now, particularly after sitting the the sun at a window shelf. It sounds like its old self, with kind of a rapid clicking sound. A few years ago when I plugged it in, that sound was missing. So I assumed the motor was dead. I'm pleased it was not. I'm letting it run in that warm environment to get it all un-gummed and turning at its designed rate.

 

 

Glad to hear that Russ.  Great looking GEM that you can be proud of.  My construction skills were limited to what pipe fittings I could kluge together using Sam Brown's book as a guide, to somewhat keep the telescope pointed upwards.


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#3767 mattyfatz

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Posted 31 October 2020 - 12:13 PM

Very cool Robert! I had one. Mine was a transitional red one. It was cool but it didn’t get a lot of use. When I decided to seriously pare things down I gave it away to a young family that couldn’t afford a telescope and wanted to start a family hobby.

That’s great Terra. I love paying it forward, especially with Astronomy.

Do you know what year that Edmund catalog page is from? I’m trying to figure out the equivalent of $280.00 in today’s $$. 



#3768 Terra Nova

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Posted 04 November 2020 - 12:15 PM

That’s great Terra. I love paying it forward, especially with Astronomy.

Do you know what year that Edmund catalog page is from? I’m trying to figure out the equivalent of $280.00 in today’s $$. 

Not sure. 1979? By the way, in 1965, the white tube model of the Edmund 4.25” on a grey pedestal GEM, two eyepieces and a barlow was $79.


Edited by Terra Nova, 04 November 2020 - 12:18 PM.


#3769 Lonnie Utah

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Posted 05 November 2020 - 07:56 AM

Just posting here for reference. I haven't been able to find a lot of photos of Q6's on the web (outside of for sale advertisments).  

 

QTI Quantum 6

Quantum 6.jpg


Edited by Lonnie Utah, 05 November 2020 - 09:26 AM.

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#3770 pbealo

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Posted 06 November 2020 - 11:12 AM

Just posting here for reference. I haven't been able to find a lot of photos of Q6's on the web (outside of for sale advertisments).  

 

QTI Quantum 6

attachicon.gifQuantum 6.jpg

There are some images in the Questar forum. Quantum owners post there frequently.

Peter



#3771 pbealo

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Posted 06 November 2020 - 11:24 AM

Here's my old Brandon 3" refractor. This is pre-Vernonscope, back when Chester Brandon owned the company. Probably made in Puerto Rico. Very late 50's or early 60's.

 

One thing I don't like about the scope are the aluminum legs with no chain or spreader. Yes. I know I can add one but don't want to add holes to the legs. I may make a triangular wooden frame with chocks to keep the leg tips from sliding out.

 

Helical focuser is a little sloppy. The built in diagonal is a good idea.

 

Anyone else have a Brandon refractor? Chester made up to 6" ones.

 

Peter

 

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#3772 adamckiewicz

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Posted 07 November 2020 - 06:50 PM

Sorry it’s a bit late but that’s so cool !!! A so enjoyable scope signed by Thomas Bopp!!!
you have to find a comet now!!! That’s definitively a keeper!! 



#3773 CharlieB

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Posted 21 November 2020 - 01:14 PM

Getting setup for a planetary showdown tonight between two classic 1200mm f/l scopes.  Mayflower 816 76/1200 (SYW) vs.  SPI (AO) 527 60/1200.  I've never compared the two side-by-side, but I'm thinking the 60mm will give a more satisfying view.

 

1200s.JPG

 


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#3774 Bonco2

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Posted 21 November 2020 - 03:33 PM

Charlie,

I'm hoping you post the results of the comparison. I'm betting on he 76mm but you never know.



#3775 CharlieB

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Posted 21 November 2020 - 05:08 PM

Charlie,

I'm hoping you post the results of the comparison. I'm betting on he 76mm but you never know.

Well, the clouds came rolling in...




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