SW Heritage 130p conversion to lightweight imaging newtonian

[bomberbaz]

Before I go into what I did, a bit of my rationale explained.  I want to carry on in spectroscopy, learning more but without committing to too much new gear, so an OTA for now whilst I continue to cut my teeth as it were.

I am using a SW AZ GTi (converted to EQ) for imaging, I want to stick with this for the time being but it has restrictions on what it can manage weightwise, SW state 5KG. The 130 P-DS is out, simply too much weight. hI had tried using a 130Mak + 0.5 reducer and played around with a celestron 130 but for various reasons, neither cut the grade. 

I was ready to give up when I thought about the heritage. I knew it was lighter (turns out almost a kilo) than the 130 P-DS but I identified that light intrusion, sloppy focuser and lack of dovetail were my biggest problems.

So I knew @moriniboy had done similar mods in the past, now after consulting with him I set about to do similar.

I got myself some stiff, black card, double sided tape, matt black sticky back plastic, a washer for the secondary and already had some spare flocking material and a vixen shoe. Also needed various tools, knife glue etc to carry this out and up front I will say, it was far more involved than I had anticipated.

 

Ok so took the mirrors off and stored safely away, removed the existing light shield and put the double sided tape inside of the top rim of the tube to accept the lightshield and made the lightshield

 

The lightshield is the measured & trimmed black card (think is is 300gm) with the SB plastic on outside, flocking directly behind the focuser and enough room for the double side tape left at the top. TIP: Wrap the cut to size cardboard around something of a similar diameter to OTA and leave overnight. This partially curves the board to give you a less stressed join when it comes to gluing. I used a full kitchen roll and several elastic bands.

For joining the tube I use PVA glue and staples to assist with the latter removed after the former had set. I also used a good quality black insulation tape to hold the join on the outside and it stuck well to the SB plastic.

Insert the rolled tube up into the OTA assembly, make sure it all marries up well then carefully remove the double sided tape backing and stick the tube to double sided tape. Without doubt this was the trickiest part of the whole operation. (TIP, I used a small clamp to hold the top part in place whilst getting the bottom started off. Deck chair peg clamps or similar would work)

Blackout the white of the double sided take as best you can. I added the vixen shoe 30mm down the tube base and added 2 small strips of loop velcro into the focuser female section inbetween the gaps in the threads. This last mod is very stiff to start with but eases as it compresses more over time.

 Sorry about the picture here but you can just about see what I mean. 

Put it all back together, collimate and bob's your uncle. 

Nearly forgot. I bought some 15mm T5 u clips to put onto the truss parts to shorten OTA to allow camera to achieve focus, these reduce the OTA by 10mm. The intention is to leave this permanently extended from here on.

I will give a first light when opportunity arises.

 

 

 

 

 

 

Edited July 13, 2023 by bomberbaz

[Alan White]

Steve, that’s a very well set out posting and the end result looks great.

I know very little about spectroscopy other than what I have listened to from a fellow Astro club member and
most recently at the BAA Comet section meeting.

How are you going to produce your spectrum for analysis?

[bomberbaz]

4 hours ago, Alan White said:

Steve, that’s a very well set out posting and the end result looks great.

I know very little about spectroscopy other than what I have listened to from a fellow Astro club member and
most recently at the BAA Comet section meeting.

How are you going to produce your spectrum for analysis?

Thanks for the endorsement Alan, I am very pleased with the results. Time will tell if it holds together well.

For spectroscopy I am using the Rspec programme. It's a very basic utility and very easy to operate. I understand there are other programmes although I believe others may be more involved and perhaps not aimed at newbs like myself. 

Just done a search and seems there are very many programmes available. When I am ready to move onto the next level I shall investigate this further but for now I shall stick with Rspec.

Anyway, Rspec allowed me to cut my teeth in this side of things and depending on existing gear, needn't be that expensive. They also provided a very useful introduction to using the programme by video. RSpec Videos – RSpec / Real-time Spectroscopy (rspec-astro.com)

 

[bomberbaz]

On 15/07/2023 at 07:52, Alan White said:

Steve, that’s a very well set out posting and the end result looks great.

I know very little about spectroscopy other than what I have listened to from a fellow Astro club member and
most recently at the BAA Comet section meeting.

How are you going to produce your spectrum for analysis?

Just realised I completely misread that Alan. I produce my spectra using a SA100 (flo sells them) and suitable mono camera.

[CHR15]

I like your set up! Is the tripod the standard skywatcher one which you colour coded red from white?

Do the u clips you use keep the telescope and camera in focus, can you post a link to the ones you've used?

Thanks.