First attempt??

[Paulus17]

Well for what seems like months of not been able to get out,due to weather and not feeling too good,i finally got out with a couple friends on Saturday night and set up my new set up for the second time since getting it and managed this image of the Orion Nebula M42.

Its not great i know but what a feeling i got when first of all seeing this beautiful sight but then managing to capture it on my own gear.

Not sure whats happened with the image but seems like the HEQ5 wasn't tracking correctly?

Any thoughts or help would be appreciated.

Image was taken using a Nikon D90,just 1, 30 sec exposure,at 800 ISO using a cable release.

[boabsta]

Well I got the same setup as you and I now know what to be trying to get next time I'm out.

I am actualy amazed you get that much detail with 1 exposure.

Also what happend with the tracking? Looks like someone knocked the scope. Were there people walking about your location? You would be suprised how just walking to/from your scope when the shutter is open can introduce vibration.

[Paulus17]

Yes it was a really great sight to see for the first time,and yes i am suprised how much detail there is for a single exposure,so can't wait till i get set up properly and doing some longer multi expos.

But in answer to your question,no nobody touched the set up,and no one was walking about,The mount was on solid ground also.

[telesto]

Hi Paul that a great first image well done

Clive

[boabsta]

Was it windy out? It looks like there was a break in the exposure as well as the light trails aren't solid.

Even untracked I dont think there would be as much trailing for 30s.

Silly questions time, was the D90 mounted directly onto focuser as body only or was it piggybacked with its own lens on? If own lens did you turn the vr off?

If mounted directly the only other things I can think off is either your mount was drunk or perhaps 1 of the legs slipped a small amount during the exposure.

I'm sure you'll find out 1 way or another next time your out.

Rab.

[Paulus17]

Thanks Clive glad you like it

Thanks Rab-No there was no wind it was still.The VR was off.The D90 was mounted directly to the focuser.

I took quite a few single frame shots,the first couple i was pressing the shutter but then attachhed the shutter release, i have seven that are like this the others were deleted as they were that bad??

The ones i pressed the shutter came out more or less the same as the ones with the shutter cable??

But as i say these were my fiirst ever attempts and i will try setting up the scope indoors and see if i can see what was going wrong.

[Keiran]

Hi Paul. thats a good first attempt, and it is a great feeling to grab your first.

Did you polar align the scope properly? Talk us through how you did this.

Did you balance the scope on the mount correctly?

The only other thing was did you knock it, but if they are all as uniformed as this, i would say it was something to do with the way you set up.

Keiran

[Paulus17]

Hi Keiran,thank you.

I did have trouble PA-ing myself so my friend who i was with done it for me.Also the mount was levelled.

I did balance the scope when the camera was attached.

We done a 1 star alignment on Vega but the scope was low down so we slewed up to it,pressed enter on the remote,then typed in M42,so the scope slewed round to M42 but once again was low,so slewed to find it,pressed enter on the remote and then i started taking images.Some were for 1minute 20 seconds as advised by my other friend there,but soon realised the GOTO wasn't tracking,so we did it all again and got the same results.??

[VigdisVZ]

Hi!

First of all, great first shot. I hope to see more of what you can come up with.

* Polar alignment, needs to be super precise. Since you didn't do it yourself, I guess you cannot comment.

* You should do atleast a 2 star alignment. I usually use Capella and Dubhe. Once I polar align properly, it slews almost bang on.

* Was the ground around the mount unstable? Just taking a step could ruin a picture.

* Camera mirror movement. Try using a black hat trick. Ie hold a black piece of something in front of the telescope when the mirror moves, and then quickly remove it. This makes sure no light is there to be registered when the mirror micro-vibrates the mount (this usually isn't that big of a deal though). You could get around this if your D90 have mirror lock, so you should really check into that.

* Wind can ruin images if it makes the mount vibrate.

I would like to see you take and post several similar exposures. We can all get a few bad frames and since the 200PDS is on the heavy end for the HEQ5 (although not impossibly heavy). So take more and see if the artifacts are persistent.

[Keiran]

I would say that all of this contributed.

Get yourself a polar finder program... whether it is for you lappy or smart phone (http://myastroimages.com/Polar_FinderScope_by_Jason_Dale/) this one is free and works, or try PolarAlign for Iphone. You will need to take a note of the GPS co-ordinates for the area you are observing in for the lappy one. Make sure your Co-ordinates as put in to your scope correctly.

This program will show you where polaris should be in your polar scope for the location, tima dn date you are observing. This is normally accurate enough for me to guide for 15mins plus.

When you turn the mount on it will ask if you are starting fronm last known position. press no (Unless you are set up in an obs, and the mount hasnt changed position since you last used it. If you are taking it breaking ot down after each use press the no).

Put in your observing co-ordinates correctly, and make sure they are definatly correct. Then when you ender the date, make sure this is in the correct format (it is normal set in the american format MM/DD/YYYY). set the time, and daylight saving.

When you have done this make sure you do a 3 star alignment. Pick 3 stars in a triangle, roughly equally spaced away from each other. one to the west, one south east and one north east for example (it doesnt have to be, but what this is doing is telling the mount where its refrence points are so it knows what the sky looks like, and it can work out where everything is).

When done correctly, you can get a few minutes unguided. you should be able to get 30secs unguided no problem..

If you are using the camera balance the scope with it on like you are. Make sure both RA and dec movements are balanced.

Hope that helps

Keiran

[jackrussell0232]

You can clearly see that it's M42, so you've succeeded already. The issue with the star trailing looks to be primarily 'wobble'. I say this because the bright points at each end of the trails suggest the scope spent longest at each end of its wobble. This does not point to a tracking rate issue and at 30s and 1000mm focal length, you'd struggle to see sub-optimal polar alignment, unless it was a long way off. Maybe the scope was feeling movement via the remote shutter cable? Would have said 'wind' but you've already discounted this.

Good luck next time.

[Paulus17]

Thank you Carl and Keiran.

The co ords i have in the hand set are for home but we went to a location about ten miles away,would that make any difference??

All the other sttings were correct,date time etc.

I'm afraid i don't have a smart phone nor take a lappy with me,but can see the benefits of one when out on location.

I will try what has been suggested next time i'm out even if its in the back garden.

I have had this new set up since September and have been out with it twice in that time.

I'm also afraid my eyes aren't so good and couldn't see a single star when trying to polar align

[Paulus17]

Thanks Jack.

The tracking was out i'd say as i had to keep using the remote to slew to keep the target center.

As i say i will set it all up indoors as i di Saturday night,apert from the polar aligning and see if anything is/was loose in the set up as i just can't how it could have wobbled it seemed solid enough to me when set up??

Also when leveling the tripod do you level in both planes,N to S and E to W or just the N to S??

[Keiran]

I level all planes, I have a little round bubble level...(http://www.ebay.co.uk/itm/1-3-4-ROUND-SURFACE-LEVEL-Center-Bubble-/271001172824?pt=LH_DefaultDomain_0&hash=item3f18edbb58&_uhb=1).

I would put in the correct co-ords, it is important to be as accurate as possible. If you havnt got a lappy or smart phone, you can always download the app at home, and say you are going to arrive at 7pm, and be set up by 730pm, set the time and date for 745pm on the app, and take a note of where polaris will be at that time (draw it on a piece of paper). Then when you get there you will know at 745pm it shoul be at 9 o'clock on the polarscope for example. You could even make note of a couple of different times so if anything goes wrong you have a back up.

Keiran

[jackrussell0232]

Sorry, when I said I didn't think it was a tracking rate issue, I meant that there was no reason to doubt your eq5 was correcting for 'earth rate' accurately, consistently moving at a rate of 15arcsecs per second, which after all, is the only thing the mount should be doing during an exposure. It isn't really 'tracking' at all, but if well aligned it should appear to be tracking the object. However, if you were having to manually apply corrections to keep the target in the field of view then the mount must have been significantly out of alignment. Were you applying corrections during the 30s of the exposure, maybe a quick prod of a low rate slew button half way through? That would explain the gap in the trails and why the mount appears to have been unsettled. It will take several seconds following any change of drive speed for the scope to settle.

Even when misalignment causes such slight drift you can hardly see it an eyepiece, it can easily cause problems when imaging. In any case, a misaligned should give you linear streaks at this image scale, whereas you have curves. So I would still suggest there is more going on here than just misalignment.

As for tripod levelling, this really helps, and is most important for the Gotos - you should always aim for this, although after a 2 or 3 star alignment, the computer should correct for it. But don't forget that even with an offset tripod, if you adjust your altitude and azimuth to get your polar axis well aligned, your tracking should be fine. Once you're pointing at your target, all the mount does is rotates the scope about its polar axis (even the most expensive ones).

Just do what we all do, keep experimenting and try to eliminate one root cause at a time. Your image is a great starting point though.

[Paulus17]

Thank you Keiran and Jack.

Good idea i will do that with the times and download that.

No problem Jack.

I wasn't doing any slewing when i was taking any exposures,but was looking through the cameras viewfinder after i had taken the shot and could see that the target had drifted out of center,so slewed it back to the middle.

So when i am polar aligning the first star can i expect it to be in the FOV or will i have to slew to get it in the middle of the FOV and then press enter,and do the same for the other two??

Or will it be way off or near abouts??

[Radar2312]

Hiya,

nice 1st go, dont wanna highjack your post but thought I'd add my first go at M42 so you can get a comparison.

I also have an HEQ5 Pro, did basic PA, 1 star alignment routine. The main difference between yours and mine is, this is a 300 second exposures and you can see the result of the polar alignment being slightly off in the star trails. What im getting at is that, with the similarity between my star trails and yours, but my exposure being 10x longer, you obviously have something more than 'slight' error in PA and I would tend to go along with jackrussell, it almost seems there was a 'nudge' part way through the exposure.

Either way, nice start and keep at it!

Rick

[jackrussell0232]

So when i am polar aligning the first star can i expect it to be in the FOV or will i have to slew to get it in the middle of the FOV and then press enter,and do the same for the other two??

Or will it be way off or near abouts??

There are actually two different topics here. The purpose of the one, two or three star alignment is to tell the mount how far up/down left/right it is, so that it can point to the right area when you do a goto. You could set it up really quite squint, correct its guesses by slewing to the stars and inserting, and the alignment routine should cope (to a point).

Polar alignment is about making sure that the RA axis about which the mount rotates, is perfectly aligned with the axis about which the earth rotates. If this is off, depending on whether you're looking east or west, the target will drift up or down (with a magnitude which increases as you approach the celestial equator). Astrobaby's guide is a great reference for the EQ5 and there's loads of info out there on how to use this drift to actually refine your polar alignment. Getting this right will make a big difference to your imaging.

Here's a DSLR shot of M42 from last week taken with an EOS550 and EQ6 mounted 800mm focal length refractor. Won't post it directly on here, because this is about your photo, and my shot is a 5 minute guided exposure, so not really comparing apples with apples. More of my images here, if you want to have a look.

With our terrible weather, always remember that you can go out on a semi-clear night to practice things like polar alignment, and just take sample shots to check your tracking. Then when it is really clear, you can do the setting up more quickly and get into the proper imaging.

[Paulus17]

Hi Rick,nice image

I would rule out the idea of a nudge or wobble because all the images were the same if not worse.Some of the stars looked like space invaders??

The only other thing i can think of what i did do was to rotate the tube so i could see through the view finder on the camera??

Is doing that advisable ??

[Paulus17]

Yes sorry Jack i did mean the star alignment,once the PA is ok.

Great images by the way Jack

[Radar2312]

Hi Paulus,

thanks, but as Jack says, this is about your image.

I've rotated my tube plenty, in order to make 'access' easier, so long as you're not doing it during exposure i cant imagine it would affect the image. My initial thought, as has been suggested already, was residual vibration from the mirror 'flipping up'. When I was looking for another scope to mount on my HEQ5, it was suggested that the weight of the 200 might be 'pushing' it. maybe that, coupled with 'mirror slap' gave you what you've got.

Like you, i'm new to this and at the bottom of a very steep learning curve, so can only offer info I've read along with my own limited experiences.

Keep at it buddy, we'll both get there!!

Rick

[Keiran]

I would really try not to move anything once it is set up, you really run the risk of undoing all of the hard work.

In ref to the aligning bit, the first star should be in the FOV, use a wide EP like a 25mm or lower, then when you have nearly centred it use a 10mm EP, this will allow you to find and centralise the star. The second should almost be spot on and the third slightly off.

As jack said even if the seeing is bad or the moon full, you can still practice your setting up.

You have more than enough to try now without getting back out there and going through all of the list we have given you, it will be impossible to know what else to suggest. I hope you get clear skies soon, and you have a better evening

Keiran

[Keiran]

as has been suggested already, was residual vibration from the mirror 'flipping up'. When I was looking for another scope to mount on my HEQ5, it was suggested that the weight of the 200 might be 'pushing' it. maybe that, coupled with 'mirror slap' gave you what you've got.

Hi Rick, i really wouldnt think it would be the mirror flipping on the camera.... I have all of the above equipment, and the scope and mount combo is fine, its only when you look at putting a guider and guide scope on top you may start to reach the limits of the mount, but i know many others on the forum use this combo guided and it is still fine. I use a 500D, and i never lock up the mirror, ive never noticed problems with the mirror flipping nefore.

Keiran

[Radar2312]

Thanks Keiran,

I bow to your greater knowledge, as I said I can only offer possibilities based on reading and limited experience.

I think the 'upshot' is, keep at it, practice makes perfect (ish)

[Paulus17]

Rick i don't mind you posting your images it was good to compare mine to yours at this early stage in our quest for perfection .

Keiran what could be wrong then if i don't get the first star in the FOV like what happened Saturday night.The scope was pointing in the right direction but was too low?

Also the first time i used the set up some weeks ago now we did the same one star alignment and we did get the target in the FOV and it did track all the time we was out,but i didn't use the camera then just visual??