Meade Deep Sky Imager. First Night Out - Tips?

[mattlane]

I recently managed to get my hands on a Meade DSI, colour one shot version (its not pro, nor is it a version 2/3) bog standard.

I've got the software all set up nicely on the laptop, and have had a play in daylight with focussing, and checking the previews (using the meade supplied capture program).

Now I am hoping that i can get out this evening, or over the weekend, does anyone have any useful suggestions, or things i should be aware of for this first night.

So far I've been doing planetary imaging, Moon, Jupiter etc, and have managed reasonable results with an unmodded SPC900, so i understand the need to capture many frames, and i have an understanding of stacking. I am aware that now i won't be shooting movies, but stills instead, and from what i gather the more stills i have, the more likely i'll resolve finer details.

I picked up some filters (more of an advance purchase) so have Skywatcher Light Pollution, and a Baader RGB and IR Cut filter set.

Also I am using a Skywatcher Explorer 130pm, reflector, with motor tracking drive (no GOTO).

I'm confident with being able to focus, and have a Bahtinov Mask I've been using with great success.

So any suggestions, or anything i should be aware of which may make my first session a success.

Many thanks in advance for advice.

Matt

[daryl_lincoln]

Hi matt

Your 1st night will be one of many disapointment and also satisfaction

Depending on how deep you want to jump in on your first night i would consentrate on focus and short exposures and use normal operation and jpeg in the save options

If you want something to do and learn on a cloudy night save in Fits and it will save 4 files (RGBL) which you can play with.

Some good guide to processing below

photo editing guide fits

FITS Liberator Tutorial

Good Luck and cant wait to see results

[mattlane]

OK, so following my first night out with the new DSI, not an entire failure although the clouds were hampering me a lot, i eventually gave up at 2am, yes i perhaps should have stuck with it longer but was knackered.

So i located a nice bright star (the one directly below M31) got it centred and got the camera on it, fairly easy, spent a long time mucking about with the focus to get an image on screen, then worked for about 5 minutes getting it nicely focussed using my Bahtinov.

All this time reading the manual, and although at first it doesn't seem like the steps are working they do follow through. So it advised me to take darks, which i did, wasn't quite expecting this to take nearly 10 minutes, by that time the clouds had rolled in and i was getting a bit weary with it, also waiting for the darks didn't help me much.

So the lessons learned from my first night, was how to focus and locate with the camera, i'm still pleased with what i managed although i didn't capture a single image i still think what i did was worthwhile.

I'm sure things will get all that much harder when i 'actually' capture but at least the first steps aren't a hassle, and i know over time i will get quicker.

What i will say (which may be of use to other users) is that i was a little taken back by the brightly coloured noise i saw when putting the camera in, i was sort of expecting it to stay dark until i focussed, and i did keep hitting the auto exposure button in the hope this would resolve, but then i gave the focuser a twist and suddenly i could see this resolving into the view of my secondary, and then finally a nice bright orange star (i could also see a smaller red and blue one as well!)

So although i didn't produce anything, still really chuffed.

Also, Daryl, I'll check out those links, thanks chap.

Matt

[SteveL]

The only real bit of advice I can give you is to look at alternatives to the Meade capture software, which is a pile of manure really Its overly complicated, makes you do things you dont have to, spend ages doing things *IT* doesnt need to do. Best thing I ever did when I got my DSI-C was to not use the Meade software.

Maybe look at getting a copy of Nebulosity.

[narrowbandpaul]

darks arent the first thing to capture....

lights are. Darks can be done when packing away.

in astronomy you need data. there is no substitute.

with a cooled sony sensor you probably dont need darks anyway....

just get loads of subs, stack em, and strecth em.

I have used the meade software, but I reckon it would be pretty bad. And SteveL certainly knows what he talking about. So get nebulosity....or something similar that can control your camera.

best of luck

[RobH]

Hello Matt.

Glad to hear that you were getting somewhere with your DSI last night.

I too started imaging using a DSI, and I'll echo what Steve says about the meade software...it nearly put me off right at the beginning. It works, but is way too complex.

You do need darks with a DSI. The camera is uncooled and there's a lot of thermal noise. As you're only going to be doing shortish exposures to begin with, it's a good idea to shoot 20 or so at the beginning of a session, and have a thermmometer ready and put the temperature the darks were taken at into the file name. The same goes for the lights. Put the temperature in the file name so you can match up with your darks later.

If there's more than a 2 degree change in temperature, shoot another set of darks.

With the DSI, it is critical that the darks match the lights to within 2 degrees or they won't work properly and you'll end up with strange streaking effects.

If you stick with the meade software (I wouldn't), there is an auto dark subtract feature which is fine unless you get a temperature mismatch, in which case you will have irretrievably messed up your lights (I've done this!)

Cheers

Rob

[daryl_lincoln]

Hi Matt

Glad your first night produced some results unfortunatlly not of the image type but still a night of learning

I get on fine with the meade software (make sure if v7.05) and find that for the learning process of focuing, and before getting to grips with stacking, and all the other processes that are involved after collecting data.the DSI can produce acceptable images (not the hubble images or some you see on here).

I found that when i started imaging i had to go back to the simple steps to learn the basics as i got fustrated, now 1 year on i feel that this played a valuble roll in where i am now.

Cheers

Daryl

[mattlane]

Thanks for the feedback chaps, much appreciated.

I've managed to get my hands on a copy of Nebulosity, works on my Mac which does make me very happy, i wasn't all that confused with the meade software, although when following the tutorial i did think i spent a LOT of my time figuring out what to do rather than actually getting on with it - does anyone know of a tutorial/guide i can follow for using Nebulosity.

Just to check my understanding, when i next get the opportunity to image i should do the following.

1, Take lights during the day, covering scope with white shirt/similar.

2, Take darks, at night before i start imaging (after equipment has cooled for half an hour)

3, Image like mad*

4, Take another set of darks at end of session.

* now one question is how should i work out how long an exposure i should take.

Fingers crossed i can get out at least one or two nights this week, although the weather reports aren't sounding promising. I think i might get someone else to buy me astronomy hopefully that way i can avoid the instant bad luck of imminent clouds when ever i buy anything.

I'll keep this thread updated with my progress in case it assists anyone else.

[Merlin66]

Your step 1 is taking "Flats" which you can use to correct shadows and vignetting in the final image.

Unless there's significant temperature variations I'd skip step 2 and only do the "Darks" at the end...

Exposure will depend on the mounting, guiding and object.

The longer the subs ie individual exposures, generally the better. get as many as you can and select the best for stacking....

[RobH]

Hello Matt.

Just to clarify...here's a simple explanation of all this calibration stuff....there's a lot more to it than this, but these are the salient points.

'Lights' are your actual images.

'Darks' are a record of the thermal noise etc of your camera. These are taken with the lens cap on and should be the same exposure length as your lights, and at close to the same temperature. With an early DSI, as I said before, this does need to be within a couple of degrees.

'Flats' are a record of your optical train which are done using an evenly illuminated light source and can be done anytime. They, when properly applied, will remove any dust bunnies, vignetting etc.

They don't have to be done at the same temperature.

'Bias' are taken at the minimum exposure that your camera will do, with the lens cap on, and are a record of the basic electrical noise of your camera.

For now, just stick to darks and get used to getting some images.

If you get too wrapped up in calibration frames etc at this stage, you'll probably end up getting confused and frustrated!

Just get yourself some images to play with, and have fun

Cheers

Rob

[mattlane]

Rob,

Good points, thanks for finally clearing up what lights, darks, and flats are. I suppose the easiest thing is to take my images (once everything is nicely cooled) and then just after take a dark at the same exposure as the images and if in doubt take a couple more.

[RobH]

Hello Matt.

Take at least 10 darks, preferably 20 or so.

This also applies to the other types of calibration frame.

If you only use 1, you'll end up adding noise.

The calibration frames are stacked in the same way as your light frames, and then the final image from the stack is applied to each of your light frames.

Cheers

Rob

[RobH]

Forgot to mention.

You don't need to shoot a new set of darks every time you image.

If you're out one night and the temperature is 10 degrees, and you're shooting say, 3 minute lights, if you have matching darks from a previous session, these will work fine.

This way, you can build up a dark frame library.

Cheers

Rob

[mattlane]

Sounds like i need to get a thermometer. Thanks for the advice, i think i 'might' be able to get an image tonight, BBc are giving their usual optimistic forecast, and have checked 'the end of the world is nigh' metcheck, and sat24 doesn't give me much hope. but you never know. Even if all i get is a good picture of a recognisable star then I'll be a happy chappie.

[daryl_lincoln]

Just on the thermometer i found one from maplins that has a digital external sensor that i could stick to the dsi as depending on the wind the dsi temp can change by 5 or 6 degree's

Cheers

Daryl

[mattlane]

OK so I've finally gotten some time behind the scope, with some clear skies and thought to update this thread with my progress. I've managed to get hold of a decent tutorial to use Envisage (yes i know Nebulosity is better, but learning curve on that is a bit higher, went for the simple step by step route). So three nights of attempts, each time i'm finding focus faster, and getting the target on the chip nicely, my motor drives seems to slip occasionally so i am getting some delays with that before i dare start imaging. 2 of the 3 times i've tried cloud has spoilt my attempts, but on one occasion i did manage to press the start button, and capture 60 images, however for some reason Envisage rather than capture sepaprate images to then combine kept saving the composite (yes i wasn't reading all the options on screen when doing this, and yes i paid for my mistake) i'd managed to get a chunk of m31 in the view. Well i think i have, but i did wonder if it was his little mate (the tiny one on the edge close to the main disc).

I'll post a pic at some point, someone might be able to tease out some detail, i had a look at DSS, but ran away scared after a few mins.

Then last night i thought i'd try something easier. M15. Directly due south, easy to find, bright stars to focus on nearby. I was ready to go. After wrestling with the motor drive, and being patient with some passing cloud my attempt was on. Then the motor drive played up again, it just wouldn't keep the object still, and by the time i had got it co-operating in came the cloud. However, in amongst all the motor drive woes, i was previewing the image at 15 second exposures, and when i did hold still i could really see a nicely packed grouping of stars, it looked like it should, and even though i didn't get a single image, i still saw it, and i know the next clear evening, I'm going to image me a Glob.

Whats really cool is although i've not managed anything with it yet, i'm not annoyed, the attempts have given me experience in the setup, which in the end will speed me up, and allow me to image more each session.

[Dave]

Hi Matt

It looks like you're slowly clambering your way up that slippery learning curve then... Keep it up.

Dave

[ncjunk]

Matt,

looks like your doing things the right way, I find going slowly and taking time to learn everything makes all the difference. The dissapointment comes for me when I expect to get something out of new equipment and fail due to lack of preparation.

I could not cope with envisage it confused the hell out of me and I now use Maxim DL (bit expensive though).

I will look forward to seeing some images of M15!

Neil C

[mattlane]

I'm not finding Envisage all that bad, mind you my plan is to simply use it to take images and not worry about the stacking (yes i know nothing about DSS, but i can learn) i think the whole process of taking darks is possibly the most annoying part as in both occasions i tried to image it was the 8 minute hold up that lost me my chance to image, in fact on my most recent attempt i cunningly took my darks while finding m15 and messing with my motor, but i just wasn't quick enough after that to get an image.

[Dave]

Matt,

Next time you see me, ask about DSS.

You'll be surprised how easy it really is to use.

Either that, or I'm using it all wrong...

Dave

[ncjunk]

Could you not just enjoy imaging for now (noting the temperature for the images) and when you can (perhaps when it is cloudy) start creating a library of darks?

I wouldn´t get too concerned with the darks for now just enjoy yourself a bit and add some darks as and when you can be bothered and have a play.

Thats what I would do anyhoo.

Neil C

[mattlane]

HAHA. Yesssss...

Clear sky. No chance of catching m15 now, too late and i can barely see him, so have had a crack at M52, just off Casseopia, and its working. Motor drive gave me the issues again, but that seemed to settle dow nicely, managed to capture about 200 images, 25 of them at 30 second exposures.

Am running it through DSS right now, see if i can make it do something nice with them. Image updates, providing get a result, will be up tomorrow!

Very exciting. Yes.

[mattlane]

Right, i thought i'd update this thread again with some results. Unfortunately I've not managed to process M52 very well yet, am waiting on a little help from a friend. But i did manage to get M15 on saturday evening.

I'm still having arguments with my motor drive, it just doesn't seem to work, or it takes forever for me to turn it on and off connect and disconnect it for it to start holding the target still. I've correctly polar aligned, and am pretty sure i've got the scope balanced - although i really want to check this with a friend in case the balance is out, and that's why nothing stays in the field of view.

So i was only able to manage 10 second exposures, with the best in fact coming in at 6-8 seconds (stars weren't trailing or blurred). I stacked around 100-130 images, and then followed a guide to stack in DSS, which did (sort of) get me a result.

I went out for about an hour last night, but gave up as my motor just wouldn't work, and it was perfectly clear - so slightly disappointed as i had high hopes for a good session last night. Although i think i really have to resolve the RA motor issue really as I'm loosing massive amounts of time imaging messing around to get the motor driving the scope.

[Beyond_Vision]

Well done for persevering I bet you were pleased to get that . It is possible to stack images on the fly with Envisage so you can see the image improving on the screen frame by frame.

Regards

Kevin

[mattlane]

I believe it is, however i decided not to, as although i stacks them it saves each stacked image, rather than keeping the individual captures to stack later. I tried that first time, and just ended up with 50 images all the same. I decided to just save each unstacked frame, then it gives me more options when i learn about DSS.