GSO 10 Inch F4 + 3 inch 0.85x Coma Corrector + 50mm Guidescope

[baj]

The scope and corrector were purchased in November last year. The coma corrector is the 3 inch TS Optics 0.85X which was sent from Germany.

The corrector has an m82 male thread which allows the corrector to be screwed directly into a focuser that has tube with an m82 female connection. However as I discovered the barrel of the corrector does fit rather well inside the focuser tube of the larger linear bearing gso focusers which are on the 10 inch and 12 inch. This did require some modification. I removed everything from the focuser until I was left with just a draw tube which has a 77mm inner diameter. I then tapped two 5mm holes for two nylon tipped screws to hold the corrector in place (see pictures). To achieve focus I then used a short metal lens hood as a spacer. The results were quite good. I have attached single un-calibrated 30 second image taken with a full frame sony a7s. Happy to email the full resolution image to interested purchasers.

The corrector comes with an adapter and t ring for canon dslr camera which achieves the correct back focus. However I also have a number of m68 spacers that could be used to achieve the required back focus for an m54 full frame connection camera. You would need an m68 to m54 adapter.

I am happy to sell the corrector + adapters and spacers for $800 postage to be paid by buyer

Otherwise I would sell the corrector + scope + guidescope + losmandy dovetail for $1250 buyer to pay postage.

[baj]

Here is a link to the sharpstar version of the corrector with dimensions and spot diagrams:


https://www.aliexpress.com/item/1005005018865346.html?spm=a2g0o.det ail.1000014.8.51722f1byZWySJ&gps-id=pcDetailBottomMoreOtherSeller&scm=1007.40050.281175.0&scm_id=1007.40050.281175.0&scm-url=1007.40050.281175.0&pvid=47f99b2f-dc6c-49f1-9a6e-0f08542613ed&_t=gps-id:pcDetailBottomMoreOtherSeller,sc m-url:1007.40050.281175.0,pvid:47f99b 2f-dc6c-49f1-9a6e-0f08542613ed,tpp_buckets:668%232846 %238112%231997&isseo=y&pdp_npi=3%40dis%21AUD%211427.0%2114 12.73%21%21%21%21%21%402101f0181684 8018741554053ee936%2112000031358207 950%21rec%21AU%21

[Nikolas]

$1400 for a coma corrector??????

[baj]

The 3 inch televue paracorr coma corrector is $2000


https://www.bintel.com.au/product/tele-vue-big-paracorr-type-2-3inch/


They are both large heavy correctors that are designed to work with full frame sensors which are extremely difficult to correct for fast newtonian reflectors such as an f4. Hence the cost.

[baj]

This is probably a niche coma corrector / 0.85x reducer so I thought I would provide some more info.

This is a link that I found useful:

https://www.stastrophotography.com/sharpstar-20032pnt-f3-2-paraboloid-astrograph-review/

This sharpstar newtonian uses the same corrector and the author describes the adapters he used for an m54 connection to the asi6200. It is one of the reasons I purchased a number of m68 spacers. However I no longer plan on purchasing a full frame camera with an m54 connection.

I have a custom made adapter m68 to m48 made by ts optics that works with dslr cameras.

There is also an m82 extension tube I had planned to buy to replace the makeshift lens hood spacer from ts optics that would be perfect since it would screw onto the m82 male thread of the corrector:

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p11531_TS-Optics-M82-Extension-Tube-with-30-mm-Length.html

Here is a link to some images that inspired me to try this corrector in the firs place:

https://www.astrobin.com/search/?q=%22TS%20Optics%20TS-Optics%20NEWTON%20Coma%20Corrector% 200.85x%20Reducer%22

[sebgod]

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