Borg ED60 Astrograph

[Gina]

Has anyone here experience of the "Borg 60ED F4 Set B06040" astrograph as sold by FLO? :- http://www.firstlightoptics.com/borg-astrograph-telescopes/borg-60ed-f4-set-b06040.html

I'm thinking of getting a Borg for my next scope - maybe in time for next winter if I can save up in time. I'm actually looking at the smallest Borg that FLO sell - the 60ED - as I want a wide-field fast scope to complement my Evostar 80 ED DS Pro. I'm hoping these scopes will be well corrected for CA as that is the problem with lenses. Most critical test is changing filters from Ha (or SII) to OIII. I have parfocal Astrodons and I don't need to refocus with the SW ED80 which makes things so much easier. I had a chance to try my best camera lens - an Asahi SMC Takumar 200mm f4 - the other night and I needed to refocus considerably. The little 60ED Borg gives 245mm FL which will do me nicely. Of course it does cost many many times the price of a camera lens but camera lenses are not designed to be used as astronomical telescopes or more correctly astrographs. The Borgs are described as astrographs and so far reports have been good for the bigger ones.

[ollypenrice]

I'm surprised that you see parfocality as an issue, especially in NB imaging, given the long hours of exposure time needed. A refocus check would always be a good idea anyway on these long runs.

I suspect that the Borg will handle everything well except the blue channel, as is so often the case with refractors and especially with small ones. (I wonder why that is. I'll ask my favourite expert.) Even the Tak FS60 is fairly disastrous in the blue channel when used for imaging. The very talented SteveL has the little Borg but the only images I see on his site are NB. http://www.steves-astro.com/ They're good, though.

My own experience with a very small refractor, the WOZS66, is that it's briliantly sharp in NB but much softer in RGB, with large star diameters.

If you track down some mini-Borg RGB images on the net I'd love to see them. In the end it's these images which will answer your question.

Olly

[Gina]

Thank you Olly - that's very helpful My technique so far with the filter wheel has been to use the 1,2,1,2,1,2, sequence but maybe I'd be better off using the 1,1,1,2,2,2 type sequence with a refocus between the different filters. Certainly if we ever get any really clear nights here with pretty much guaranteed several hours clear the second sequence would be fine. I'll search out Borg 60ED images anyway.

[RAC]

Both my canon 200mm f2.8L and canon 400mm f5.6L need a small change in focus between ha and olll but they are both very sharp with and i like them alot, the 400 at 5.6 is a little slow though. I'm currently testing a Mamiya 300mm f2.8 medium format lens but keeping internal reflections down is hard with such a big fast bit of glass without stopping it down to f4 and defeating the whole purpose.

[Gina]

Both my canon 200mm f2.8L and canon 400mm f5.6L need a small change in focus between ha and olll but they are both very sharp with and i like them alot, the 400 at 5.6 is a little slow though. I'm currently testing a Mamiya 300mm f2.8 medium format lens but keeping internal reflections down is hard with such a big fast bit of glass without stopping it down to f4 and defeating the whole purpose.

Thanks for you reply My 200mm f4 Takumar seems very sharp over the sensor size of both Atik 314L+ and DSLR when used for NB and refocused for different filters but I need more clear nights for imaging. I shall certainly be imaging with this lens for some time (as well as the SW ED80) and will be developing an electric focussing system for it. Comparing my M31 image with one taken with the Borg 60ED and DSLR, mine seems little worse than the Borg one - and I may be able to get my focus better.

[Gina]

Here are some Borg 60ED images resulting from a Google search :-

Gary Honis-modified Canon XS(D1000), Hutech 60ED F3.8 (Mini Borg) astrograph with 0.66X focal reducer/flattener, 240sec, ASA 1600, Digitally developed in PS CS3. Mount: Astrotrac TT320X-AG TW3100 Wedge and TP3065 Pier.

[Gina]

This is my M31 taken with 1100D and 200mm lens :-

[ollypenrice]

As I'd have expected the NB is the best of the ones you found, Gina. The first of the Sagittarius Triplet images has magenta bloat which I'd suspect came really from the blue. (I don't see it coming from the red, anyway, and it can't be the green.) However the blue control in the second one seems decent though the signal isn't very strong in blue. Note the Trifid.

So, encouraging.

Olly

[RAC]

Here's a lagoon and trifid shot i did with my 200mm 2.8L and 1000d to compare with the above shot. The Canon 200mm f2.8 is alot cheaper. And with NB and the chip size of your 314 you can use f2.8 no problems. With a dslr f3.5 and an external aperture mask clean it up perfectly.

And whats more is its an awesome daytime lens!

Lagoon Trifid widefield by meg rac, on Flickr

[Gina]

Excellent image I admit to be going slightly off the Borg at £1250 plus carriage. I couldn't afford it for at least 6 months anyway. Meanwhile, I'm getting electric focussing set up for camera lenses. I'm covering the mounting etc. in a thread in the "DIY - Astronomer" :- http://stargazerslounge.com/topic/174206-wide-field-mounting-for-atik-314l-with-camera-lens/

[Naemeth]

What confuses me, and I hope you don't mind Gina, is the fact that Canon lenses seem to be much cheaper than their short APO refractor counterparts, why is this? Is it just cheaper to manufacture camera lenses because they are more mass produced or have had more money invested in them to develop the product?

[ollypenrice]

I've just sold a Canon 200L and, in all honesty, I think it whacks the WO ZS66 into next week. It might do likewise for the Borg judging by the comparator images so far. But you have the hassle of getting the chip spacing right and sourcing a slide drawer for mono imaging with a lens. I don't remember who makes the slide drawer but someone does.

Olly

[Gina]

What confuses me, and I hope you don't mind Gina, is the fact that Canon lenses seem to be much cheaper than their short APO refractor counterparts, why is this? Is it just cheaper to manufacture camera lenses because they are more mass produced or have had more money invested in them to develop the product?

Yes, exactly - mass production equals cheap. Well cheaper. Wherever there's only a small market the development costs are spread over a small number of sales so the cost per individual is higher.

[Naemeth]

Yes, exactly - mass production equals cheap. Well cheaper. Wherever there's only a small market the development costs are spread over a small number of sales so the cost per individual is higher.

I was about to ask if they make lenses that go up nearer 1000mm, and I just spotted this monster:

http://www.canon.co.uk/For_Home/Product_Finder/Cameras/EF_Lenses/Telephoto/EF_800mm_f5.6L_IS_USM/

It's a bit slow though.

[Gina]

I've just sold a Canon 200L and, in all honesty, I think it whacks the WO ZS66 into next week. It might do likewise for the Borg judging by the comparator images so far. But you have the hassle of getting the chip spacing right and sourcing a slide drawer for mono imaging with a lens. I don't remember who makes the slide drawer but someone does.

Olly

I now have adapters to fit M42 x 1mm theaded lenses (Pentax/Praktica thread) onto my EFW2 and achieve focus. You can also get Canon EF bayonet to T2 adapters to achieve the same. The next problem is attaching the assembly to your mount. No nice straight cylinder to use scope rings and no tripod bush on the camera. Without a filter wheel you can use that device you had (I believe) but there isn't room for that. Large guide scope rings can be used though. There is a neck of adapters and the first part of the lens that will take the adjusters and I guess you could use another on the camera. Unfortunately the 314L+ has a large diameter - the better ones are a better shape fir this. Then there is the focussing problem...

[melsky]

Hi Gina

Another vote for the 200L lens, I picked mine up secondhand for £425, I also have the SMC Takumar 200 F4 as well and now that I have an OIII clip filter in addition to my HA I'm thinking of trying a dual setup of modded Canon 600D 200mm canon L HA filter and my unmodded Canon 600D Takumar 200mm OIII filter, I'll let you know how it goes it the meantime here's my M31 shot with the Canon lens.

Mel

[Gina]

That's excellent I reckon that excels the Borg 60ED from the images I can find. Of course the image qualirty depends on the operator as well as the equipment.

[htj]

Regarding mounting Canon lenses onto mounts, Geoptik produces this one

http://www.geoptik.com/en/scheda-prodotto/30a189/214/30a189.html

[FLO]

Here's a recent image made using the Borg 60ED f4 and a modded Canon 450D.

Other than that picture from the DigiBorg blog I am not going to try to influence you towards buying a Borg over a DSLR lens but this discussion is far too interesting for me to stand on the sidelines because it is something I have been pondering and having spent two decades working in photo-retail (prior to FLO) I can see how both optics are attractive.

Convenience and practically aside, it is difficult to make an objective comparison between a Canon EF 200mm f2.8L II USM and a Borg 60ED f4. The Canon lens comprises nine elements in seven groups. I haven't been able to find a schematic for the Borg 60ED f4 but it is essentially two components (a doublet objective with triplet reducer) so we know it has five elements. I have requested schematics but for now let's assume they are all separate elements, that would give us ten air-to-glass surfaces compared to the Canon's fourteen. In theory the less air-to-glass surfaces there are the better it is for light transmission, contrast and freedom of ghosting from internal reflections. But we can't rely on that because there are other differences like the Canon lens features two ED elements compared to Borg's single ED element. But we don't know what ED glass is used (neither manufacturer is likely to tell us). We cannot easily compare lens coatings and overall quality of manufacture, though I wouldn't expect to find a problem with either product. We can consider reputation, but they both have excellent reputations. Ideally we would arrange a side-by-side comparison but that isn't easy to organise and there is a difference in focal length.

Ultimately both are excellent optics so it will probably boil down to price and practicality. If you are predominantly interested in terrestrial photography then the EF200 is a no-brainer and can be adapted for astro use. It is also considerably cheaper. If astrophotography is paramount and your pockets are deep enough then the Borg with it's all-metal construction, built-in camera rotator and modular system is more attractive.

Whichever route you take I am sure you will produce some marvelous images

Hope that helps,

Steve

[Gina]

Thank you Steve Very interesting