Astrophotography with the OM-1 and the Oly f/5.0-6.3 100-400mm

A bit over two years ago over at the Narrowband Channel on YouTube, Ben recommended the then-new Olympus f/5.0-6.3 100-400mm zoom lens for astrophotography, both lunar and deep sky. Although I didn’t follow his advice immediately, a year ago I purchased this lens from Schiller’s Camera in St. Louis and a few weeks later purchased the OM System OM-1 from the same vendor, trading in my EM-1 Mark III and several lenses to do so. Over the following months I discovered this lens-camera combination produced fantastic results for butterfly and bird photography (e.g., pelicans, eagles, and cardinals), but I didn’t really get going using it for astrophotography until I acquired the Sky Watcher Star Adventurer GTi late last November. Unfortunately, winter began shortly thereafter and with winter come clouds. Lots of clouds. But I have been able to try out this entire camera-lens-mount combination during a few good evenings this winter and thought I should present my results from photographing the Running Man and Orion Nebulas, the latter considered by many astrophotographers to be the most beautiful of the deep sky subjects.

This image is the result of stacking 33 150-second images (82.5 minutes of total integration time) taken on the evening of January 20, 2023, from my house’s rear deck, which is made out of wood—the worst surface for maintaining a steady camera setup.  The skies in my city of 125,000 are rated as Bortle 8.  To facilitate the tracking process I used guiding with PHD2 software, a ZWO 120mm guide scope, and a ZWO ASI120MM-S guide camera. In addition to the 33 150-second lights, I also made dark, flat, and flat dark calibration frames which were used in the stacking process. The 33 light images were taken with the aperture wide open at f/6.3 and an ISO of 1000 (recommended by Ben for the OM-1). The lens was extended fully to zoom in at 400mm. After acquiring these images, I stacked them in ASTAP (thanks to Ben for recommending this program) and processed the stack in PixInsight and Photoshop. The result is the image below, with which I am very pleased.

I hope this image demonstrates how well the OM-1 and Oly 100-400mm in combination can do DSO astrophotography and will encourage others to use this combination for astrophotography.

Note: Ben and his Narrowband Channel are focused on astrophotography using Olympus gear as well as dedicated astrophotography cameras and telescopes. Thus this channel is a useful source of information for micro four-thirds users who wish to pursue astrophotography with their equipment.

Al

The Running Man and Orion Nebulas taken on the evening of January 20, 2023

Killer shot!

Remarkable!

joeletx wrote:

The details of what seems to be cloud layers is amazing! I have just ordered this lens for shooting birds, the moon and such, with my E-M1 III. It also come with the EC-20 2X TC. I got inspired by your work. May be once I am fully retired, I can get into astro shooting.

Thank you.  Good results can be obtained of the moon with the 100-400, and with the TC, you can likely fill much of the frame with the moon (I don’t have either Oly TC).  One thing I failed to mention in my original post was that I used the OM-1’s Starry Sky autofocus feature set to achieve focus accurately.  The E-M1 III has that feature too, and I highly recommend using it for astro although the regular autofocus works well for the moon.  There are a couple of videos on the Narrowband channel over on YouTube about using the 100-400 to photograph the moon, and I think they would be helpful to you as you begin using this lens to photograph the moon.  Post processing is the key to producing good astro images, so I concur that being retired will really help by providing more time to learn those skills.  I’m retired, so I can speak from experience.

Good luck as you give this a try.

Al

Thank you very much to Matt, Off, Gary, Rob, Joel, and Glass for their enthusiastically positive response to this image.  The affirmation is appreciated greatly.

Al

Great image (and obviously some good processing in your part)!

Can I ask if you tried using the 100-400 on the Star Adventurer GTI *without* guiding?  If yes, what sort of exposure times were you getting before star trailing was evident?

Bialykot wrote:

Great image (and obviously some good processing in your part)!

Can I ask if you tried using the 100-400 on the Star Adventurer GTI *without* guiding? If yes, what sort of exposure times were you getting before star trailing was evident?

Thank you. The processing was a combination of PixInsight and Photoshop after stacking in ASTAP. One of my sons and my wife bought me PixInsight for Christmas, and I've been on kind of a crash course to learn that complex program since then. Got enough to be able to use it as part of processing the Orion-Running-Man image. I should say that Pixinsight does require a serious commitment to learn how to use it--and I still have a lot to learn.

As for the Star Adventurer GTi without guiding, I did that once, back after it first arrived in late November. The subject was the Pleiades, and I used the OM-1 mounted on the 100-400 with the lens set to a focal length of 300mm, aperture f/6.3, ISO 1600, and a shutter speed of 120 seconds (25 images x 120 seconds for a total integration time of 50 minutes). To my eye only 1 of the 25 images showed what might be considered star trailing although it could have been me moving on the wooden deck where I had things set up.  This was the first time I actually used the GTi, although I had practiced indoors a few times to try to learn how it worked. So I used it successfully with an exposure time of two minutes (120 seconds) per image the first time out. And this was with the lens at 300mm, which is a field of view equivalent to a full frame at 600mm. This was just a first-light trial run, so I probably didn't know everything I should have about using the equipment. Nevertheless, I think it was successful. I did take calibration frames, and stacked the images in ASTAP and processed the stacked image in Photoshop. I'm attaching the processed photo so you can see the stars, and this was before I got Pixinsight. I think if I work on it, I can process it better, but I haven't done that yet.  I regard this as just a see-if-I-can-get-the-equipment-to-work try rather than a serious attempt to photograph the Pleiades; nevertheless, the photo below shows what was produced.  Since then I haven't tried any other unguided sessions, because conditions have been so few and far between that I wanted the best images I could capture, and I thought guiding would do that.

I hope this helps.

Al

The Pleiades star cluster taken on the evening of November 25, 2022.

Thank you (and another great picture).  Good to know the GTI can handle the 100-400 plus OM1 payload.  I have a GTI tracker on order (and already have the OM1/100-400) but am completely new to Astrophotography, although keen to try.  Auto guiding might be of interest at a future date if I take to the new hobby, but want to keep costs low for the moment.  But you’ve certainly proved that the kit is capable of good results (in the right hands of course), so that’s very encouraging.

Hello, long time reader and first time poster here.

I have a question regarding exposure times for astrophotography with your setup. I also live in a populated area (Bortle 8). I've attempted long exposure photos of the sky with my Panasonic 100-300MM II. I get almost completely washed out and over exposed images of even relatively clear sky (no clouds) with exposures over 30 seconds @ f/5.6, ISO 400.

How did you manage individual 150-second exposures in your 33 image stack? I don't feel like I could get even close to that. Curious what an individual, unprocessed light frame looks like before stacking and calibration with dark and flat frames.

Bialykot wrote:

Thank you (and another great picture). Good to know the GTI can handle the 100-400 plus OM1 payload. I have a GTI tracker on order (and already have the OM1/100-400) but am completely new to Astrophotography, although keen to try. Auto guiding might be of interest at a future date if I take to the new hobby, but want to keep costs low for the moment. But you’ve certainly proved that the kit is capable of good results (in the right hands of course), so that’s very encouraging.

Thank you for commenting positively about the Pleiades image.  Because you have a GTi on the way, I thought I should share a couple of things I have learned that might help you avoid some significant problems with it.

First, never, I repeat, never use a planet to perform any of the star alignments one performs for maximum accuracy before using the GOTO capability.  I thought I had a defective unit because during the three-star alignment, on the second or third object, the GTi would slew and end up pointing the camera and lens toward the ground!  I finally called my vendor, High Point Scientific, for techinical support, and the advisor I spoke with figured out what was causing my problem when I mentioned that I had been using Jupiter and Mars as objects in the star alignments.  He told me never to do that, and that the problem wasn't limited to the GTi as it was a general problem with these kinds of equatorial mounts.  He said the manuals don't say anything about this, but he has experience with several different mounts, and using planets for the alignment is trouble.  Big trouble.  I had used those two planets because they are so bright and would be easier to identify on the camera's back screen after the GTi would slew to them.  The target object needs to be identified because although it may be in the frame, often it is necessary to use the SynScan software controls to place the object in the exact center of the frame.  Sometimes the object will be almost exactly centered, but not always.  So only use stars for star alignment even though the software will list Jupiter or Mars right now at the top of the list of available target options.

Second, and again the manual is silent on this point, the mount has two locations on the front for attaching the counterweight shaft that holds the 5.5-pound weight used to balance the camera-lens assembly.  One location is for middle and fairly high latitudes and the other is for lower latitudes.  What I discovered is that using the attachment point for the middle latitudes--I'm at 39 degrees north--the counterweight must be positioned so high on the shaft that it will come into contact with parts of the mount during slewing.  The solution is to use the attachment point for lower latitudes.  The counterweight must still be positioned high on the shaft, but it will be well out of the way and not come into contact with any part of the GTi during slewing.  This is not just me suggesting this solution, but there are at least two video tutorials on YouTube that note this problem and recommend this solution, one of them being from High Point Scientific itself.  The advisor I spoke with also endorsed this solution.  This entire problem is caused because the OM-1 and 100-400 lens together form a relatively light combination, around 3.8 pounds.  Even when I add a vixen dovetail plate and my guide scope and camera along with lens warmers, my total payload comes in around 5.6 or 5.7 pounds, and the GTI's maximum load is 11 pounds.

I hope these two recommendations will save you from having several fruitless nights under the stars.  And good luck as you begin this journey.

Al

Szymon Ciski wrote:

Spectacular! I'm curious though if you could have got similar results with your EM-1 Mark III.

I no longer have my EM-1 Mark III because I traded it in, along with some lenses, to help finance my purchase of the OM-1.   I did some astro with my Mark III and got good results, but I don't really have any apples-to-apple comparisons.  Except for their dimensions, the two cameras have completely different sensors, so I would expect some differences.  However, would the differences be differences that really make a difference?  I don't know.  But I do know one can do good astro with the Mark III.  And, obviously, with the OM-1.

Al