[VoiceOfReason]

Okay, here's some of the stuff from last night, and it isn't all that good in quality, but I am sharing it anyway.. It tells me I needed to get the counterweight set right (duh, knew that) because the tripod was partially in the way (maybe a new, dedicated tripod too., causing things to be off balance and it to mess with tracking some, that I need a 77mm Bahtinov mask for focusing or to prefocus in the daytime and tape the focus ring down like I normally do, and that I really need my 150-450 to come back from being repaired again ASAP. So, last night's play with the new mount results are in and I need to work on my technique a little, but you get the Crab Nebula, parts of the Orion nebula complex (Flame Nebula, De Mairan's Nebula, Orion Nebula, Horsehead Nebula, part of Bernards Loop), Pleiades, M41, Sirius, and what I think is NGC 2360. Enjoy, and look for much better results in the future!

In case you're wondering the mount is an iOptron Skytracker Pro and the counterwweight kit is the iOptron 3311 (not the right one for the kit, but it can work with the right adapters, yeah, I was stupid in ordering it) and a generic ballhead from Amazon. I think once I get things set I can probably pull off 2+ minute exposures. The most I tried last night were 20 seconds, which when the camera was facing south ended up good, facing off axis, not so good at times due to the setup being a little off balance.

So, if anyone has advice in allowing the nebulosity to show, but minimizing clipping highlights I'd love to know. Also, how to keep the noise out, because these have fields of grain in them. Also, critique my technique because frankly these pics suck compared to some I see, and I want to get on their level, plus I can get a glimpse of what this setup is capable of when done right. All images taken with a K1, Tamron 70-200 f/2.8, and DA HD 1.4 Teleconverter. I really want

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Last edited by VoiceOfReason; 03-21-2017 at 06:34 PM.

[DeadJohn]

Those are great results for the first night with new equipment.

Yes, I think almost any motorized mount is "better" than the astrotracer. Better = opportunity to take multiple images for stacking without having to keep repointing your camera.

if anyone has advice in allowing the nebulosity to show, but minimizing clipping highlights

how to keep the noise out

If those were 20 second exposures, you probably shot at a high ISO which cuts your available dynamic range. Lower ISO and longer exposures can give you more processing leeway and less noise.

Always shoot in DNG format, or DNG+low resolution JPG. Small JPGs can be used for quick tests of stacking setings, then go back and redo with the DNG.

Learn how to stack multiple images for improved signal/noise ratio. In rough terms, doubling the number of images cuts noise in half. IMO 8 images are a good starting size for stacking because that doesn't take too long to capture data. As you get more experience, and with dimmer targets, you can increase your stack sizes.

Deep Sky Stacker is good free software. I use it with my K-5 but have yet to test it with my K-1.

Astrophotography is a mix of fun and frustration. A friend of mine says "if it was easy I wouldn't do it".

[jbinpg]

Check out the Astrophotography social group. Many of us have been through where you are now. Two absolute necessities for astro are a bahtinov mask for focusing and a remote release to trigger the shutter. You will want to keep your hands off the equipment once everything is set up. I tried the 1.4 HD TC but did not like the edges of the frame so ditched it. The iOptron is a nice piece of kit.

[VoiceOfReason]

Those are great results for the first night with new equipment.

Yes, I think almost any motorized mount is "better" than the astrotracer. Better = opportunity to take multiple images for stacking without having to keep repointing your camera.




If those were 20 second exposures, you probably shot at a high ISO which cuts your available dynamic range. Lower ISO and longer exposures can give you more processing leeway and less noise.

Always shoot in DNG format, or DNG+low resolution JPG. Small JPGs can be used for quick tests of stacking setings, then go back and redo with the DNG.

Learn how to stack multiple images for improved signal/noise ratio. In rough terms, doubling the number of images cuts noise in half. IMO 8 images are a good starting size for stacking because that doesn't take too long to capture data. As you get more experience, and with dimmer targets, you can increase your stack sizes.

Deep Sky Stacker is good free software. I use it with my K-5 but have yet to test it with my K-1.

Astrophotography is a mix of fun and frustration. A friend of mine says "if it was easy I wouldn't do it".

I do always do DNG to one card, jpeg to the other. DSS will choke on K1 files. .dng? Not going to happen, and the jpegs simply give an image with white lines, if it doesn't end up failing. I was shooting at ISO 3200 and 6400, which probably contributed to my problem.

[VoiceOfReason]

Check out the Astrophotography social group. Many of us have been through where you are now. Two absolute necessities for astro are a bahtinov mask for focusing and a remote release to trigger the shutter. You will want to keep your hands off the equipment once everything is set up. I tried the 1.4 HD TC but did not like the edges of the frame so ditched it. The iOptron is a nice piece of kit.

I noticed smeary edges with the 1.4 tc. My big Bahtinov mask is great for my 150mm refractor, but too big for the lens I was using. I did order a 77 mm one today, so that's on the way. Any advice for turning up the gain enough to get diffraction spikes? The ones I got from Sirius were too small and I didn't use my prefocus cheat that I normally do because I was too late to do it in daylight, and the moon wasn't out so I missed the alternate way. I did join the AP group that I had no idea existed until last night.

[DeadJohn]

Focus: Aim at a very bright star, turn on liveview, get rough focus without any liveview zoom (if unfocused you won't see the star on the LCD), then maximize liveview zoom on that star and finetune focus until the star is as small as possible. Carefully re-aim at your target without touching the lens.

[VoiceOfReason]

Focus: Aim at a very bright star, turn on liveview, get rough focus without any liveview zoom (if unfocused you won't see the star on the LCD), then maximize liveview zoom on that star and finetune focus until the star is as small as possible. Carefully re-aim at your target without touching the lens.

If it is clear enough tonight I will give this a shot.

[AstroDave]

Dead John has it right for focussing.

Try an ISO of 400 or 800, as noted above. Your Orion nebula is overexposed.

You won't get diffraction spikes with your set up. The spikes you see in many astronomical photos really are due to diffraction from the struts (usually 4 of them in a cross pattern) that support the secondary mirror or the focus equipment in a reflecting telescope. With a standard camera lens, there are no struts to make the spikes! Astronomers would be just as happy to not have the spikes (although they are useful for astrometric measurements, where you can set your measuring equipment on the spikes).

[VoiceOfReason]

Dead John has it right for focussing.

Try an ISO of 400 or 800, as noted above. Your Orion nebula is overexposed.

You won't get diffraction spikes with your set up. The spikes you see in many astronomical photos really are due to diffraction from the struts (usually 4 of them in a cross pattern) that support the secondary mirror or the focus equipment in a reflecting telescope. With a standard camera lens, there are no struts to make the spikes! Astronomers would be just as happy to not have the spikes (although they are useful for astrometric measurements, where you can set your measuring equipment on the spikes).

I will try those ISOs. I meant about the diffraction spikes for using a Bahtinov mask for focusing to make it easy mode. I will try the LV and zoom in method for focusing next. Also, any tips on exposure times to stop that overexposure in the core of the Orion nebula?

[jbinpg]

Actually, it is easy to get diffraction spikes with a DSLR depending on what lens you are using. Here is an example with the DA*300/4:



Notice the spikes around blown-out Iota Orionis below M42. They are caused by the aperture blades: 9 blades give an 18-spike pattern.

[VoiceOfReason]

Actually, it is easy to get diffraction spikes with a DSLR depending on what lens you are using. Here is an example with the DA*300/4:



Notice the spikes around blown-out Iota Orionis below M42. They are caused by the aperture blades: 9 blades give an 18-spike pattern.

Ohh, I got them in some of the pics (see Sirius), but what I was looking for is how to get them when focusing for use of a Bhatinov mask. Also, I am jealous of that pic.

[jbinpg]

Here is how I do my setup:

1) Turn off AF on lens and camera body. I have a bunch of User settings for Astro so I just need to spin it to the right one. Attach lens to tripod.

2) Level the tripod. Can't trust anything if you do not do this. I suggest hanging some weight from the center column for stability.

3) Align tracking mount on celestial north.

4) Start tracking mount. Remove lens hood and replace with bahtinov mask.

5) Find a nice bright star for the bahtinov mask, say mag 1 or 2 or brighter if you have it. Stay away from planets. You want a specular light source.

6) Frame with star in center then hit LV button, then the OK button. This will magnify LV image.

7) Adjust with direction buttons until bahtinov image is in center of frame. Then carefully rack focus back and forth until central diffraction spike exactly bisects star image.

8) Carefuly remove mask and replace with lens hood. Orient to target and fire away!

Using a bahtinov mask is superior to trying to find the smallest star image since it only takes the smallest turn of the focus rack to spoil your focus. Careful that you do not touch lens after achieving focus or you will need to refocus. Good idea to check focus after a while anyway since it may drift due to thermal fluctuations. And we have all had the experience of tripping over a tripod leg in the dark which means you get to do it all over again from #2.

[SKYGZR]

You won't get diffraction spikes with your set up. The spikes you see in many astronomical photos really are due to diffraction from the struts (usually 4 of them in a cross pattern) that support the secondary mirror or the focus equipment in a reflecting telescope. With a standard camera lens, there are no struts to make the spikes!

One will get "flairing" spikes if the lens is stopped down. To avoid, use step down rings to "stop" down the lens.

[VoiceOfReason]

Finally got stuff working for 30 second exposures. I need an intervalometer.