Where next after the MN190 ?

[MartinB]

Cat - stop stop stop it now!!! An MN300, AG12 - get your thinking cap on matey otherwise you might as well indulge in a years worth of very expensive self flagellation. Yes, you might be able to get an AG12 teetering precariously on your mount but an OAG will help you very little (short of reducing the weight from impossible to just about conceivable). You are asking for a lot of grief as your NEQ6 huffs, puffs and wheezes to correct it's guiding errors and every little sigh of breeze gives your guiding graph apoplexy. Get yourself an AP1200 or something with similar umph before you think of changing that MN190.

Instead, give your itch a good scratch and stick with the kit you've got. An NEQ6 and MN190 should be good buddies. Familiarity with your kit is probably worth at least £2 000 in kit upgrade when it comes to getting results - smoother set up, all the foibles understood and managed = less battling and more imaging.

[LDUNN1]

I have a Canon 5dmk2 which I have been using for astrophotography.

BUT, I'm a total novice only starting in astro-anything earlier this year (although I've been 'into' photography for 25+years & use the 5d2 for non-astro use since I bought it in 2009 as an upgrade from a 20d).

I bought my first astro mount (nEQ6) of any kind in feb/mar of this year.

I only tell you all this to put my comments into perspective, but I have some experience with some of the equipment mentioned throughout this thread.

The 5d2 does have a relatively large sensor being same size as 35mm film (36mmx24mm) - with 21mp giving 6.4 micron sized pixels. The low light capability is excellent - at least a couple of stops better than my 20d (which also has same sized pixels but on a smaller chip). Most of the current Canon DSLR range with APS sized chips have smaller 4.8 micron pixels - smaller pixels can mean poorer signal-to-noise ratios. Consequently, with the 5d2 I am comfortable running at 1600 iso while those on canon APS bodies are runing at 800 iso - & despite being at 1600, the noise is better too.......I could probably run at 3200 iso & get similar noise results to the aps sensors running 800 iso. This is based upon my experience with daylight use, & a little astro use.

From starting to use the EQ6 in March until August, I have just been using my 5d2 on the nEQ6 with normal telephoto camera lenses, where most of the time I've been wrestling & learning the basics of using an EQ mount, polar alignment, 3-star alignment, Laptop control of mount & camera & adding a guiding system into the mix.

Having learnt the basics, mid year my thoughts turned to my first imaging scope. I looked at the 190MN too - AND had the same concern that using a large sensor your run into vignetting issues. I found someone on SGL who had used a 5d2+190MN & they sent me an unprocessed sub - horrible vignetting. You end up cropping so much of the image away, you throw away the advantage of a large sensor - what's the point?! the 190MN was off the menu.

The other issue / advantage (depending upon what you are doing & how you look at it) with a full frame sensor is that you capture more of the sky.....ie you effectively lose magnification vs an image out of a smaller sensor. on the Canon system the APS sensors give an effective 1.6x magnification effect on the focal length of the lens so a Canon 100mm lens behaves more like a 160mm on a crop/APS sensor vs the 100mm on a full frame 5d2. Great for wide field, not so ideal for most galaxy/planetry use......but you can always crop heavily with so many pixels!

With this in mind I looked at 'scopes with slightly longer focal lengths to get a better compromise - knowing that I can still use my long telephoto camera lenses if/when I want to shoot wide field.

What I've ended up with is arguably less than ideal, & it is very early days yet, I've only used it 4 times & two of those have ended up being 'de-bugging'/tuning sessions, & the remainder being 'quick looks' at lots of differnet subjects to get a 'feel' for the new scope & what scale it gives. I've yet to really collect a decent amount of data on one astro subject.......& even if I had, I know my post-processing skills astro images are very lacking. BUT what I have ended up with is a 1988 AP 152mm f9 Starfire with the 2.7" focuser. Yes, it is a tad slow for imaging (I have an AP 0.75x telecompressor on order, which should help), but it has a FL of 1370mm & with the large sensor I still get 1 deg x 1.5 deg approx in the frame at prime focus......which, with the small use I have had so far, seems a good compromise for me.

More importantly, is that I am not suffering much vignetting - there is a slither around the edge of the frame in various places which is noticeably dark - BUT I am not convinced that this is down to vignetting entirely - if it were, I'd expect it to be more of a spherical nature with the corners noticeably darker than mid way along the edges - & that is not exactly what I have. The amount I need to crop from the extremities of the frame is minimal however, so I am not too concerned just yet......& I also have an AP EOS adapter which gives a less of an optical restriction into the camera than the adapter I am currently using (1.5" vs 1.875"), so this may totally eliminate the darkened areas around the edge I currently have.

When I have something worth posting here with this combo I will......but it may be quite a wait as my skills have to catch up with my equipment now ;-)

[Komet]

Familiarity with your kit is probably worth at least £2 000 in kit upgrade

Oh well said ..... I totally agree with this. It can take ages to actually understand your gear and how it works.

[markcol]

Hear, hear Martin!

Well done for injecting some common sense into things. We can get carried away with gear purchsing when the thing that makes the biggest difference is the weather and sky LP quality.

Having an obs is the best upgrade in my book.

cheers

Mark

[Catanonia]

Thankls all, Have other scopes and an obs.

Was looking for the future and something to save up for like we all do.

Don't tell me you wouldn't like that 16in dob one day

[Komet]

I wouldn't like that 16" dob one day .......

I mean that also.

[Uranium235]

Not sure whether you have thought about this yet - how about getting two of everything? You could probably get 2x APOs and 2xCCDs on the NEQ6 (maybe theee if CF tubes), Olly seems to be getting along quite well with using OSC and Mono at the same time (though on different mounts).

Edit: Or... another idea would be to try and mount an additional APO on top of the MN190, it would be a slightly shorter FL for sure, but if you use that to shoot colour frames then it will only needs a bit of re-sizing to get them to match your mono L or Ha frames (not tough if you have the software). Not sure if youre mount will take it though being the MN190 is a bit weighty to start off with. Surely these options would be way cheaper than forking out for an AG12?

[ollypenrice]

Not sure whether you have thought about this yet - how about getting two of everything? You could probably get 2x APOs and 2xCCDs on the NEQ6 (maybe theee if CF tubes), Olly seems to be getting along quite well with using OSC and Mono at the same time (though on different mounts).

You beat me to it. Quite seriously I think that the high quality of semi budget scopes means that a parallel rig of 2 similar scopes/cameras would trounce a finer scope working solo and costing a comparable sum.

If I had two of the Altair 115s and 2 cameras I am certain that I would get a better result than I could get from the TEC alone. I bought the TEC second hand but even so it came out at two new Altair 115s plus £600 towards the second camera.

Increasingly I work with megaloads of exposure and, believe me, it is absolute bliss. You can sharpen things into the nines and stretch way, way harder for the faint stuff. Noise? It isn't there.

It doesn't have to be One Shot Colour and Mono. It can be two monos, though filters aren't free other than on OSC cameras. I have two setups to offer more to the guests and trying to run two mono setups at once would kill me. That's why one is colour. On the same mount it wouldn't matter.

So... 2 scopes, 2 cameras? Yes, seriously, a brilliant idea.

Olly

[Whippy]

If I had two of the Altair 115s and 2 cameras I am certain that I would get a better result than I could get from the TEC alone

You're not suggesting that the Altair is a better scope than the TEC are you Olly?

Tony..

[Starblazer]

I think he means twice as much data in the same amount of time with a parallel set-up of 2 Altairs would be better than 1 lone TEC imaging for the nite.

[Tim]

IMHO a 'frac would be a backwards step. If you can master the finer points of imaging with a fast newt, and the associated processing, then more aperture seems an obvious place to go. Be interesting to see how Peter Shah feels about the swap from 8" AG to a 12"AG.

I'm waiting till Olly gets an AG16 before booking my trip to Les Granges

[Catanonia]

IMHO a 'frac would be a backwards step. If you can master the finer points of imaging with a fast newt, and the associated processing, then more aperture seems an obvious place to go. Be interesting to see how Peter Shah feels about the swap from 8" AG to a 12"AG.

I'm waiting till Olly gets an AG16 before booking my trip to Les Granges

Agreed and hence the question by me. AG12 and new mount would be something to save for.