Intes Micro Mak Newt for imaging?

[900SL]

I see that you can still get a couple of the Intes MNs, the 56 and 76. 

The 56 is 127mm aperture and 760mm FL, the 76 is 178mm and 1050 mm.

The 76 is probably too much for my Vixen SXD2, but the 56 could be an interesting scope to pair with my 533MC

I've read quite a few reports that they had great optics and mirrors back in the day, comparable to a good APO, but heavier and with dew a risk with the front glass.

Are the current models still well made and likely to perform well for astrophotography? With the 533mc I'd have a much narrower FOV on the 56 than my current GT71, so would open up longer DSO targets. The 56 is not too heavy either..

[Carbon Brush]

I can't comment on the MN56/76 directly. I have the longer FL MN78.
Excellent superb optics. Solid build. A definite keeper.
Well I got it in 2008 I think and have never been tempted to sell.

[StarryEyed]

There is a lot of competition these days from semi apos and the more economical apos. for the price. But thats not to take anything away from The Intes or Intes Micro MN's. Not sure their still made unless its a special order or just old stock. Still I would love one out of curiosity and a steal at the price seven or more years ago. 

edit..

Widescreen have stock which is a surprise to me. I hankered for A MN58 for a long time. 

Edited June 17, 2022 by StarryEyed

[900SL]

Yes that's where I saw them. I'll drop them a line

[Dan_Paris]

Most of the models are optimized for visual, so even if the optics are superb  the fully illuminated field is quite narrow (few millimeters) and their backfocus is rather tight (40mm for the MN76 fitted with the original low-profile focuser, according to Widescreen Centre).

Edited June 20, 2022 by Dan_Paris

[900SL]

On 20/06/2022 at 22:55, Dan_Paris said:

Most of the models are optimized for visual, so even if the optics are superb  the fully illuminated field is quite narrow (few millimeters) and their backfocus is rather tight (40mm for the MN76 fitted with the original low-profile focuser, according to Widescreen Centre).

Yes but I think the MN56 is more suitable for AP.  I've seen it advertised as visual/imaging on a couple of retailers websites.

Backfocus appears to be 40mm which rules out DSLRs but it would work with my 533MC pro.

I'd love to know the size of the image circle as it might work with the 11mm square sensor on the 533MC. I'd then have a 760mm FL scope with APO like quality for not a lot of money..

[Dan_Paris]

On 24/06/2022 at 11:20, 900SL said:

I'd love to know the size of the image circle as it might work with the 11mm square sensor on the 533MC. I'd then have a 760mm FL scope with APO like quality for not a lot of money..

The problem is not so much the size of the corrected field but of the fully illuminated field.

I did a quick computation, the fully illuminated field of the MN56 is about 2mm only. At the edge of the 533MC sensor, you would have about 82% illumination. It is ok but you would not be able to upgrade to larger sensors in the future (at the edge of APS-C you have about 50% illumination).

 

Unless you strongly dislike star spikes, I think that an ordinary Newtonian is more suitable as an astrograph. An 8" f/4 with a coma corrector  has about the same focal length, physical length and weight,  but gathers 2.5X more light and has a far larger illuminated circle.

 

The MN has probably  better optics than an average mass-produced Newtonian, but if the optics of the latter are decent it would not make much difference in deep sky AP (and of course one can choose high end optics for the newt).

 

 

 

 

 

 

 

Edited June 25, 2022 by Dan_Paris

[900SL]

Thanks Dan, appreciated. I could live with the 82% illumination if the optics are as good as owners report. Flats should cope with the drop off at the periphery 

With the 533 I theoretically have 1 arcsec/pixel and 0.85 degree FOV, so pretty useful for lunar and DSO 

An equivalent triplet refractor with field flattener would set me back at least twice  the cost of the Intes.  

I hear what you are saying about the logic of getting a newt, but I'm kinda stuck on the idea of a MN

 

[Herbert West]

I have a second-hand MN56 that I originally bought for a stupid low price for imaging, intending to use it with the 533. It would work ok-ish. Small chip and short optical train (no filter wheel) would do the trick. Then, however, I managed to get a good deal on ASI1600 + wheel + LRGBSHO filters. So, what was I to do? I bought a second-hand SW MN190 🙂

That left me with the MN56 for visual use and it's fantastic, but I still wonder how the MN56 would perform with a camera. Please post pretty pictures if you make any!

Edited June 30, 2022 by Herbert West

[GalaxyGael]

I have and love my Intes MN56. Its the old version with the pebbled greige tube, and the awful helical crayford focuser, which I used for imaging a year or more ago. I use a 90 mm apo at the moment, but getting the MN56 back into imaging mode and found this thread while trying to sort out what thread is on the focuser base.

I chipped the secondary when removing the front corrector (it tilt rapidly when you start to remove it) and replaced it with a large secondary that illuminated by APS-C (ASI2600MC). It corrects well out to APS-C but as the mirror was much bigger than the secondary holder, the curved stick-out edges created interesting diffraction spikes on edge stars. I've since replaced it with a 29 mm mirror that fits, and collimation was near text book perfect again.

I know i will have severe illumination fall off with the APS-C, but at ~1"/px resolution (being at or just a bit to brave for my seeing), it will be used at 760 mm for galaxy imaging  with cropping, or up close work. It is wonderful in terms of color correction of course, and no spacing to deal with at focus. I think I have a better handle on imaging to get the best out of it now, so looking forward to it. It strikes me that it would be great with the player one or new asi planetary cameras, which are highly sensitive, good pixel size options and the clean dark frame and shorter exposures can deal with the noise.

Stunning with an eyepiece, no newtonian I have seen is flocked like these. It even has 1 cm tall knife edge baffles opposite the focuser, and 6/7 more down the tube. Mirror cell is also great, full circumference holder, no diffraction from 3 mirror clips. I changed the small locking screws with M5 allen bolts, easier to tighten everything down.  Also, weight balancing is good, between corrector and the mirror. The metallic dew shield, like the OTA, is wider than the mirror and house about 4/5 knife edge baffles also. Such a rich field view, and does give the top end 4in APO a run for the money

Apologies hijacking the thread, but can anyone who has this scope (min is in the attic right now behind a lot of stuff!) tell me what the focuser attachment threads are? I remember M66.5 or something odd, but I'm searching for focusers for it.

Here was mine sometime last year on the old rig way before the sun faded everything.

[900SL]

I'm looking forward to seeing how you get on with rejuvenating your MN. Good luck!