M42

[Dave Saunders]

After seeing Darryl's fantastic photo of M42 I'm rather embarrassed to show you my effort, but perhaps you could give this novice some advice?

This photo of M42 was taken last night, seeing was pehaps a bit hazy with almost a half Moon. It was taken with a Meade LX90/3.3 Reducer and Meade DSI. The scope on a wedge but as you see by star trails not very well aligned (I need to practice star drift more!!). I took 60x30sec exposures and stacked with Registax,post processing was a bit of try it and see ,at the moment I dont understand all of it!!.
My picture seem's a bit dark and lacking in colour, should I have used longer exposures or shorter exposures and more frame's??

Hope you can give your expert advice as one day I'd like to take a photo that would not look out of place in the gallery.

Thanks Dave

[Darryl]

Hi Dave,

Where is the picture? Could you provide a link or was there a problem uploading. The best place to upload your pictures is the image gallery. You can then link to the picture in the gallery from a post in the forums. The gallery provides a ready made link after you upload.

Regards,

[dmill1220]

Hi Dave,

I can give you a bit of advice on to how to simplify and speed up the drift align process with a wedge, by using the DSI live view window, this also lets the camera get up to operating temperature before you take your dark frames.

If your interested let me know and I will post the steps that I use.

As far as your image You need to try to upload it again, if you tried to post it as a BMP, the file may have been too large.

If you re-open the image with registax and save it as a Jpeg, it will reduce the data size.
I look forward to seeing your image of M-42

Dennis

[Dave Saunders]

Sorry guy's, forgot to downsize i think, hope it's come through this time.
Yes Dennis that would be helpfull.

[Darryl]

Hi Dave,

I am thinking some of the things that could be going on right now is your polar alignment is off. Focus could be tuned up a bit. I can't immediately nail down the color issue. Is there any point in any of your shots that you see some red, such as before you put them in Registax.

I take it that it's a Meade DSI Color, or are you using filters on a monochrome CCD camera?

If others can comment that would great as I am no more an expert or have any more experience than any of you when it comes to Astrophotography. I enjoy these threads as I like learning and hearing everybody's comments, it's not uncommon to pick something up that you hadn't thought of or heard before that can suddenly transform your shot into works of art, well almost .

Regards,

[Dave Saunders]

Yes Darryl I am using Meade DSI colour with no filters. I've downloaded the same pic after a bit more tweeking with Jasc Paint Shop Pro 9.
Not sure if it look's any better but it is red!! I tried to match colours to a pic. taken by Hubble,so it must be right.

Getting the right focus is not easy,I have a hartman mask with 2 holes that help but seem's not good enough, maybe i'le make a defraction mask and see if that's any better.
Would I be right in thinking that if "seeing" is not that good getting 99.9% focus is unlikly?? so getting good focus is more about choosing the right night?? Dave

[dmill1220]

Hi Dave,

Sorry that its taken me a while to get back to you, I have a lot of other things going on right now.

To me it looks like you do need to do better with the focus, but its mostly a polar alignment problem as Darryl has stated.

Give Me a little time to get some screen shots posted, I'll have to fire up my laptop and get it online I will post the step by step process with some screen shots and sketches.

Dennis

[Darryl]

Hi Dave,

If you are using a DSI Pro then there was no need to reduce the actual dimensions of your image, just the size of the file (the space it uses on the hard drive). A high to medium quality jpg would be fine.

If you had good color data in the shot to begin with using a DSI color you shouldn't have had to push the red that hard if at all to make the orion nebula show its color. Light pollution or not enough data could be something that's going on, but I can't say for sure.

Focusing will be more difficult with bad seeing. Even if you were as close as you could get to perfect focus with bad seeing the image would still appear softer than if you had steady skies, unless your post processing skills are good then you may have a hard time telling the difference.

I for one try and get the best shot I can with the telescope and camera and then do the least amount of processing I can get away with. Sometimes nothing will bring an image back from the depths and then its time to move on and try again. When I go out to image I never know if I am going to get something worth keeping (to me) or not.

[Dave Saunders]

Hi Darryl,

Thank's for your reply, o'boy there's more to this astrophotography than meet's the eye (no pun intended). Photography has been my hobby all my life from my box browny to 35mm Pentax and now digital Fuji S7000, so I wont let this beat me!!

What's odd is I can get spot on focus when just viewing, easy, even without hartman mask's etc. So why is it sooooo difficult with a little DSI.
With a laptop screen to see it in , should have thought it would be easy. By the way my DSI is just the bog standard DSI not the pro.

On the Meade Envisage screen there is a zoom facility that if you want zoom's in on your target, would it help do you think to zoom on to, say a close star and focus, then zoom out, would the bigger target still be in focus???
It look's as if it might be clear sky's tonight so maybe I'le give it a try, half the fun is the challenge ( I keep teling myself).

All the best Dave.

[dmill1220]

HI Dave,

To simplify the Drift align process with the DSI on a EQ wedge, you must not use a focal reducer!. First Roughly polar align and Auto 3 star align with a medium power eyepiece and no reducer, then you install the DSI.

The longer focal length means shorter waiting periods to see which way a star drifts in the field of view of the DSI, in between wedge adjustments.

The camera orientation will depend on whether you image with or without the diagonal, the sketch I made for you, shows you how the DSi should be placed when viewing South, if you live in the Northern Hemisphere, and with a diagonal, and with or without the focal reducer installed.

Without the Diagonal when imaging, the Usb port may need to point to the left.

When you focus using a Hartman Mask your settings in the DSI should be set to: Deep sky, MONO, Dark -subtraction is not enabled, the live view box is checked, with the exposure in the live view box set at 1 second, and the Auto contrast should also be checked.

when you start the actual drift align process with the DSI installed, you need to pick a star at your meridian and the Celestial EQ that is bright enough to register in the Camera's live view mode.
The settings I gave you give you the best sensitivity to accomplish this and in Mono, it helps to reduce noise on your screen.

I Do not use the Zoom Function when focusing with a Hartman Mask.

If your camera orientation is correct, and once you have an alignment star centered in you live view screen, draw a centroid box around a star and then place your mouse cursor over the + that is in the middle of the centroid box.

Do not move the mouse! and notice which way the star drifts you will see the centroid box center moving away from your cursor placement.
Ignore any left to right drift, the drift up or down becomes evident very quickly in this manner.

You then adjust your EQ wedge in azimuth, to get the star to move in the direction of the drift, when you adjust the wedge in Azmuth, the star will also move in RA, so you will have to keep it centered in the live view window with the RA drive axis of your hand controller.

Continue with the Drift align process for the Declination adjustment move the wedge up or down depending again on which way the star drifts without rotating the camera in the holder, just move the wedge in declination towards the direction of the drift, and keep it centered with the hand controller RA axis again.

Repeat this whole process all over again to correct for any minor misalignment from the last step, again do both the RA and then the DEC axis in the same manner.

After you have drift aligned you must repeat the Autostar 2 or three star alignment just for goto accuracy, every alignment star should be centered in the DSI live view window again, this time youre not touching the Mount, you are aligning the software to an accurately polar aligned mount.

The final step is to remove the DSI, install your focal reducer, and refocus using the Hartmann mask again.

When you start an imaging run Select two bright stars at either end of the screen for image de-rotation, and keep the combined box checked. adjust your sliders and shadow enhance, to a level that you like with a preview full length sub. if you plan on 30 second subs set your first preview to 30 seconds, and hit the preview button.

With this option Autostar can stack an image more accurately than third party software.

I will get into better color accuracy on another post with the DSI.