[smigol]

+1.
I am lucky to get 12 second exposures before LP gets out of hand. I can`t even start to comprehend 1200 sec.

The idea is to try to get signal above the noise floor of the camera and at the same time, not get the skyglow more than 1/3 of the full well capacity of the sensor.

I've done the math for my home site and my regular dark site and I've split the best values as much as I can. See point #4 on this post regarding noise floor and sky glow.

TL;DR: I'm compromising the proper duration I should be using at home (maybe 400-600 seconds) and proper duration I should be using at the dark site (maybe 1800 to 2400 seconds) for convenience of having just one library of files for calibration.

[MJSfoto1956]

shot last night from 30 miles south of Boston, looking northeast towards Ursa Major (The Big Dipper). While there was obvious city "glow", the K-3 sensor is pretty good and the image cleans up well. Using the Astrotracer together with the 60-250mm at 250mm f/4 I was just able to make out two messier objects:



the full-res version is here: All sizes | Pentax K-3 + DA* 60-250mm + Astrotracer @ 250mm @ f/4 @ 40 seconds @ ISO 1000 | Flickr - Photo Sharing!

[Iksobarg]

Someone is getting ready to ROCK & ROLL...

My odometer hit 44 today but I'm about as giddy as a little gushy eight-year-old girl.

[smigol]

Someone is getting ready to ROCK & ROLL...

My odometer hit 44 today but I'm about as giddy as a little gushy eight-year-old girl.

What's the filter on the IDAS? With a non-full spectrum cam, you should be able to use just the IDAS filter.

Remember to focus on objects 1/3 from the center to give best focus across the field.

[Iksobarg]

What's the filter on the IDAS? With a non-full spectrum cam, you should be able to use just the IDAS filter.

Thanks Stephen. I thought I was being overprotective with the UV filter over the IDAS. Taking the UV off then.

[MJSfoto1956]

quick question: so if I have a series of celestial shots taken with Astrotracer w/ 250mm @ f4 and all the center stars are pin points, as are the upper left, lower left and upper right, however, with the lower right quadrant showing slight "donuts" I would assume this lens is slightly de-centered -- any agreement with that analysis?

Michael

[smigol]

quick question: so if I have a series of celestial shots taken with Astrotracer w/ 250mm @ f4 and all the center stars are pin points, as are the upper left, lower left and upper right, however, with the lower right quadrant showing slight "donuts" I would assume this lens is slightly de-centered -- any agreement with that analysis?

Michael

The doughnuts point to some element out of best position. What you describe does seem like it's not centered well.

Do you have an example that you can share? I'll run it through CCDI and see what it shows regarding centering and tilt.

Someone is getting ready to ROCK & ROLL...

My odometer hit 44 today but I'm about as giddy as a little gushy eight-year-old girl.

A perfect target for testing that setup now is M44 or the Beehive. Good wide field, lots of stars across the area, well placed in the sky. Could be done with a lot of short exposures since it's all stars and no nebulosity.

---

Last edited by smigol; 03-07-2014 at 11:29 PM. Reason: added quote

[VisualDarkness]

I went on a trip to the north with a bunch of other students and we got really lucky with the weather and activity one evening. K-5 + DA 14/2.8

[smigol]

I went on a trip to the north with a bunch of other students and we got really lucky with the weather and activity one evening. K-5 + DA 14/2.8

Very nice, I've not seen the Aurora in person. Have you tried video or timelapse?

[Parry]

I recently bought an as new, mint Meyer Optik Gorlitz Orestegor 300/4.

Is this any good for taking pictures of the moon?

[VisualDarkness]

Very nice, I've not seen the Aurora in person. Have you tried video or timelapse?

Yeah, a pretty bad timelapse but I messed up and have to redo and upload a new version.

[interested_observer]

I recently bought an as new, mint Meyer Optik Gorlitz Orestegor 300/4.

Is this any good for taking pictures of the moon?

It should work well. There's a thread on it from several years ago... It does appear to be a bit on the heavy side ~5lbs.

• https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/33906-300mm-lens-question.html

[smigol]

I recently bought an as new, mint Meyer Optik Gorlitz Orestegor 300/4.

Is this any good for taking pictures of the moon?

I found some examples of the lens on flickr. The FOV of a 300 mm lens on APSC is 187 x 279 arcminutes. The size of the moon disc is 29.3 – 34.1 arcseconds. You'd still need to do a fair amount of cropping to feature just the moon when using this lens.

Important to note that the large number of aperture blades should reduce the star effect on high contrast edges. That alone would be useful to retain good separation of light and dark features near the terminator.

Since you already have the lens and the moon is up, why not shoot some and see what you get? Remember that the surface of the moon is lit by sunlight, so the sunny 16 rule is your guide for proper exposure.

[Tsuken]

I've just come in from my backyard, where I shot this, my first catch of the Orion Nebula:

Messier 42 - The Orion Nebula by -Occasionally Focused-

I'm absolutely over the moon. (This is processed from a jpg, until I load the RAW onto my computer; the iPad does many photographic things well, but tricky RAW files ain't one.)

[Iksobarg]

Really fine work!!
I'm a little jealous...
gonna catchup someday