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Equipment all ordered, where do i start?

milan

By milan
in Imaging - Discussion

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milan

milan

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So ive just ordered the last bit of the Jigsaw (Field Flattener) from FLO which should hopefully be here tomorrow. So the next question is whats nice simple object to start with? (Im interested in DSO's)

Also my understanding with focus is that i point at a nice bright star (Vega is nice and clear from our garden) and attain focus on that? (first by using eyepiece and then replace with camera). I presume that if i note the grade scale on my focuser i should be able to use that position all the time? (subject to minor tweaks)

I understand the concept of shooting the image (ISO 800) but in terms of length of exposure does this come down to experience? (im not guiding yet so should i be looking at less than 1min exposures?)

I also understand how to get darks, but what about lights? Would shooting a piece of white paper be good enough? or does temperature need to be the same as the flats and darks?

All excited now and cant wait to give it all a try. :o

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barkis

barkis

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The Pleiades (M45) Is a nice target, and very popular. All that beautiful nebulosity to record, and it never fails to impress.

You need an imaging expert to advise you on the flats etc. though.:o. Good luck with your imaging career, it is very addictive.

Ron.:)

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arad85

arad85

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For focus, get yourself a Bahtinov mask... remember that the focus plane of the camera will be different to an eyepiece so you need to focus with the camera in place.

For exposure times - for DSOs, as long as you can get away with without star trails. I've managed 90sec ones on my CG5, but I'm getting better (i.e. more experienced) with setting up the mount. The length of time you can go without any star trails is directly determined by how good your polar alignment is.

As to darks and lights, perhaps take a look here: DeepSkyStacker FAQ as the light frame is the one you are taking with teh camera :o I think you mean what about flats - often taken at dusk or dawn. See the link for what you need to do.

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glennbech

glennbech

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Hi! I assume you will be imaging with a DSLR? I would suggest that you download or buy a software package for imaging. I'm currently using DSLR Focus, but I would not recommend it. I'm moving to something else. (DSLR Focus) The software will let you take a series of images, while you adjust focus manually. Different mechanism exist in the different software packages to aid you in focusing (.. by telling you how small a star is etc.)

As a first target I'd suggest M31. It's very bright, and you're guranteed results .-) If you cannot get longer exposures, don't be afraid to increase the ISO to 1600 and take more frames instead.

You don't need flats straight away. I'd suggest that you just go out and image your target and get as many exposures as you can, and Stack them. (deep sky stacker). You can use Gradient Xterminator (plugin for photoshop) or PixInsight LE to do a background extraction to remove vignetting.

Flats. To do basic flats I usually begin my imaging session at twilight, just before visible stars. I take 13-17 images of the sky *opposite* to the sun (east). I adjust my exposures so that they are "half way" exposed (like the auto function would use)

It's important to take dark frames for the flats as well, if not, you'll end up introducing noise with your flat frame. Cover the scope and take exposures at the same ISO and lenght as your flat frames.

All these frames

- "light" for example M31,

- "darks" (exposures at the same length as your "light" but with the scope "closed")

- "flats" (sky opposite of sun during twilight)

- "flat darks" (exposures at the same length as your flats, but with the cover on)

Go into ---> "deep sky stacker" (DeepSkyStacker - Free) to "align & merge" multiple images and calibration frames into one.

Take on step at a time, and don't be shy with questions!

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milan

milan

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Yes im going to be using a Canon 5D (Mk1)

Im going to have to go with nebulosity as we are a 'mac' household, although saying that i do have an old PC knocking about so could potentially use that come to think of it (but its not a laptop)

Dont worry im sure there will be plenty of question! :o

As for the Bahtinov, just found stay focused so thats sorted :)

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jgs001

jgs001

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It's worth having a look at VMware Fusion for the Mac. DSS works perfectly in there, and if you already have it .... Start out with a few open clusters... nice easy targets... you don't need real long exposures, like you would for the neb in M45 etc and they look grand in a large starfield. Something like the M's in Auriga and Gemini. Or the double in Perseus.

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milan

milan

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Your welcome :) Spending your money for you has been almost been as enjoyable as spending mine :D:o (just I don't have the EQ6/WO....)

LOL!

Does the Bahtinov have to go on a particular way round? i.e. angled slots on right or left? (when looking at front of telescope) Also, which way do you turn the focuser depending upon which side the diffraction spike is? (im sure i will get this when i try, just looking for some experiences :) )

We can easily see Pleiades from our garden so would this be a good starting point?

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arad85

arad85

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The mask just "sits" on the front of the 'scope, and you'll find the angled slots naturally are on left & right with the vertical slots below - although it doesn't matter which way the mask is on. You just balance it on with two screws that are supplied with it. As to focusing - it's obvious when you try it. You want to get all 3 lines to cross at exactly the same point. When you are in focus, this happens, when you are out, one line moves against the others so you get 3 crossing points. As you focus in or out, the line moves further away.

Pleiades would probably be be a good start - but you'll need to be careful not to over expose. Take a few test shots first at different ISO/exposure times and see where the histogram of the resulting image is. Adjust accordingly....

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glennbech

glennbech

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Beware that you need 4-5 minute exposures on the pleiades to get the nebulosity. At least at f/5ish of the Megrez 90/0.8 reducer.

BTW: I own the Megrez 90 myself. It's an awsome imaging scope, and a lovely travel companion! :-)

A lot of the images on my blog was taken last year with the M90.

Looking forward to see what you can get out of your equipment.

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glennbech

glennbech

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"I assume the later? as i dont have guiding (yet :o )"

I am afraid you'll need between exposures of 4-5 minutes to bring out the nebulosity in M45. If your skies are good, shorter will do! For DSO's "Sky is king". Maybe 1-2 minutes and ISO 1600 will do? I guess you'll have to find out :-)

This image is a 4 x 5 minute exposures.

Other targets that will be great to start with

- The "ET cluster" & all other open clusters in Cas.

- The Double cluster

- M36 + M37 + M38 in Auriga ( I hope I am right here...)

Targets that will look great with lots of 1-2 minute exposures

- M31

- M42 (When it climbs higher)

- mmm.. Can't think of more...

You'll need to get guiding I to get into imaging of nebulae I think. It might be that the EQ6 is capable of longer subs with good polar alignment. You should check that out!

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arad85

arad85

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Hi Milan,

The camera "sees" the F ratio as "unknown" as it can't communicate with the lens. It doesn't matter what you set it to - the camera can't affect it anyway, nor does it affect the exposure as you are controlling it manually :o

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milan

milan

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Okay so ive just taken my first one minute photo of the M31!

First question on my DSLR screen the image has an orangey tint, light pollution? There is also some vignetting but i presume this is cause my 5D is full frame?

Im very excited! :o

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