287 replies to this topic

[Jay_Reynolds_Freeman]

The fully loaded weight of the 510 is listed as 250 pounds. However, that would be with all of the accessories loaded including the guidescope and Unihex. The general-purpose configuration shown above is a bit lighter. The heaviest single component is the equatorial head which is about 75 pounds, though I'd like to weigh it just to find out for sure as this is bt far the heaviest element. Everything else breaks down into manageable parts.

P.S.

Note where the counterweights are in the picture above as compared with the picture of the fully dressed scope at NEAF.

Do you know what the OTA weighs all by itself, with (e.g.) just the dew shield and finder attached?

[Airship]

I just checked... with just the dew shield and finder the OTA weighs in at 23 pounds. Not bad at all.

[Airship]

While I was at it I knocked out a set of 6"x6" wooden pads that are of various thicknesses. These can be stacked under the tripod legs to get it very close to level which makes aligning the setting circles a bit easier. I thought about this for a _long_ time, but the final solution was very simple. I wanted something simple, super sturdy, and safe to use at an outreach. Simple is good...

 

 

Another safety add-on was adding a bump guard to the counterweight shaft. I got a nasty cut on my forehead one evening after a _long_ night of star-hopping. I thought that getting this fixed was important since we use the 510 at outreach events quite a bit and I didn't want anyone having a similar encounter...

 

 

Last but not least, this is another safety issue setting up a large refractor. With such a long tube you have to be _very_ careful as you add accessories and the tube balance shifts. It can be a bit nail-biting as you add a lot of weight and then have to shift the scope in the cradle to keep it balanced and under control without it getting away from you. The fix was to make a monopod to support the tube while the telescope is being assembled. I pondered several simple designs, but what I ended up with is a tad crude, but it works really well with this and my other large refractors. It's a clean, fluffy paint rolled on a long adjustable handle held upright with a camera tripod attached with straps of Velcro. In use, the height of the pad is set to the same as the cradle. The telescope is placed in the cradle and secured in its normal, balanced configuration. Initially, the weight of the telescope holds it firmly to the mounting assistant. As accessories are added the weight on the mounting assistant slowly comes off the pad and after the last bit is added I can gently lift the (now balanced) scope off of the mounting assistant as set it off to the side. Taking the scope apart is the reverse procedure.

 

 

Works great!

 

[Airship]

After enjoying the view of Venus before sunset and a bit of star-hopping during the early evening I switched over to imaging mode to garb a picture of the full Pink Moon before the clouds rolled in. This involved replacing the 2” star diagonal with a Canon EOS Ra full frame mirrorless camera fitted with a Baader Fringe Killer (Minus Violet) filter. The camera was controlled by Backyard EOS and the focus was set using Arcturus and a homemade Bahtinov mask...

 

 

The slow-motion controls on the stack 510 mount made pointing the telescope very easy and the tracking was excellent. Setting the focus was quick and easy, and the whole process was very smooth. 

Edited by Airship, 13 April 2025 - 06:49 PM.

[Airship]

...and this was the final result...

 

 

The Baader Fringe Killer did a perfect job removing the last traces of any chromic aberrations. I didn't have to do _any_ special processing of the final image.

 

The Full Pink Moon - 4/12/2025, 22h30m EDT
Telescope: Unitron 510 5” f/16 refractor, stock configuration
Camera: Canon EOS Ra full frame mirrorless
Filter: 2” Baader Fringe Killer (Minus Violet)
Exposure: 256x1/2000sec, ISO 3200, saved as RAW
Seeing: 4/5
White Balance: Nebulosity Automatic
Software: Backyard EOS, Autostakkert, Registax, Nebulosity, Photoshop

 

[deSitter]

...and this was the final result...

 

Moon (4-12-2025)-2j.jpg

 

The Baader Fringe Killer did a perfect job removing the last traces of any chromic aberrations. I didn't have to do _any_ special processing of the final image.

 

The Full Pink Moon - 4/12/2025, 22h30m EDT
Telescope: Unitron 510 5” f/16 refractor, stock configuration
Camera: Canon EOS Ra full frame mirrorless
Filter: 2” Baader Fringe Killer (Minus Violet)
Exposure: 256x1/2000sec, ISO 3200, saved as RAW
Seeing: 4/5
White Balance: Nebulosity Automatic
Software: Backyard EOS, Autostakkert, Registax, Nebulosity, Photoshop

 

OK you need a challenge..

 

1 - one - astrophoto made with the bellows camera! Just 1. I've never seen even one -1. 

 

 

-drl

[Jay_Reynolds_Freeman]

I just checked... with just the dew shield and finder the OTA weighs in at 23 pounds. Not bad at all.

Thank you for providing that information: I was curious, because I have a 152C, shown over here, and its OTA with just dew shield and finder weighs 12 pounds. I was wondering whether the weights scaled in proportion to the cube of the linear size, and they do: (5/4)**3 is 125/64, so the expected weight for the 510 would be 24 pounds or a little less.

 

Clear sky ...

[Airship]

Coolness!

 

Speaking of the Unitron 220 camera… I have a _lot_ of experience with plate and sheet film cameras. I would dearly like to do some tests with the Unitron 220 camera. Unfortunately, I got rid of my darkroom kit a long time ago. Still, I am curious enough to put at least a basic kit back together. The 220 should be perfectly capable of taking basic pictures of the sun and moon. Deepsky… I’m going to go with no. I have taken deepsky images with the stock 510 using a modern camera and that worked okay. Soooo… yeah, I can see experimenting with the 220 camera sometime this year.

 

Neat stuff.

[ccwemyss]

It takes almost nothing to do contact printing with black and white. I do it all the time (but then I also consider 220 to be small format). Too bad you didn't mention it before NEAF. I could have given you a Beseler 35 enlarger with medium format carrier and lens -- my school is getting rid of its darkroom equipment. 

 

Chip W. 

[Airship]

Ahah! The Plan is to develop the sheet film as per usual, then photograph the negatives with a digital camera. Way back when I did a lot of work with large format roll film along with 4x5 and 5x7 inch sheet film. I built my own cameras as well. My one and only picture of Comet Halley was taken with one of my 4x5 sheet film cameras. I recently recovered my very first astrophotos from the early 1960s. They were star trails of Orion and Ursa Major taken on 120 roll film using a Voightlander Bessa II. The prints are long gone, but I still have the negatives. Ahhhh, I can still smell the chemicals…
 

[ccwemyss]

4x5 and 5x7 are medium format in my darkroom. 8x10 is at the low end of large format. The real thrill was the time I got to use one of the 20x24 Polaroids. 

 

I still have my father's Bessa II, which was the gateway drug into large format when I was in my 30's. The Kodachromes it made were phenomenal. 

 

Let me know if you decide to go back to real printing and want an enlarger. A 48MP camera should capture the resolution of a fine grain 2.25x3.25 negative, and if you bracket and use HDR processing, you can get most of the dynamic range. 

 

Chip W. 

[combatdad]

OK you need a challenge..

 

1 - one - astrophoto made with the bellows camera! Just 1. I've never seen even one -1. 

 

 

-drl

This is a lunar photo I received from an individual in Texas some years ago.  He said it was taken in 1963 with his Model 220 camera on a 4 inch Unitron and processed with his enlarger at F8 for 3 seconds.

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[deSitter]

This is a lunar photo I received from an individual in Texas some years ago.  He said it was taken in 1963 with his Model 220 camera on a 4 inch Unitron and processed with his enlarger at F8 for 3 seconds.

 

Good start

 

-drl