ISS Transit in front of the sun

On Sunday, May 1st, I was lucky to have the ISS transit the sun only a few kilometers away. Weather played with my plans as well. So i packed my solar scope and drove to a place right in the center of the transit line.
The transit itself is a very brief event. This particular one lasted for less than 2 seconds. So everything hat to be well set up before the clock reached 08:24:22 CEST.

This image is a combination of 15 individual images captured in 1.02 seconds. The solar surface was further enhanced by a stack of 880 frames adjacent to the transit itself.

M90 Galaxy

This is my first image of Messier 90. It is not yet as good as I would like it to be. Which is due to bad weather preventing further imaging. As the moon is already too bright, I will have to postpone further imaging at least to the next new-moon phase.
Nevertheless, this image shows already a beautiful spiral galaxy with its companion.

Image data:
Date: 2021-04-15 – 2021-04-16
Location: Graz, Austria
Telescope: 10β€³ f/5 Newtonian with GPU corrector (1250mm focal length)
Camera: QHY183M @ -20C
Filters: Optolong RGB + Baader UV-IR-Cut
Guiding: MGEN-II with off-axis guider
Exposures:
UV-IR-Cut: 45x120s, Gain 0, Offset 15
R 30x120s, G 25x120s, B 23x120s, Gain 10, Offset 15

Powering a Sony mirrorless camera for timelapse or astrophotography

During the last years I frequently ran into trouble with the stock Sony batteries. Neither of the camera – battery combinations I had, were capable of imaging more than approximately 4 to 5 hours (some cameras drained their batteries within less than 2 hours). So I tried to determine the optimum means of powering a Sony camera for several hours without the need to change batteries. Here is, what I came up with:

Option 1: Batteries with increased capacity
Several after market companies offer compatible batteries with increased capacity. These batteries are also offered at more than competitive price tags.
In my experience, most of these batteries do not provide the capacity as imprinted. There are units, which significantly exceed the stock batteries. But you may also get a battery, which is outperformed by the stock battery – even though it is offered at twice the capacity.
If you are lucky and you have a well performing battery, you may extend the time in operation by 10%-50%.

ProCon
– economic price
– up to 50% longer operation
– no external units required
– does not last a whole night
– capacity labelling may be misleading

Option 2: USB power supply
Several – and at least the new models – have a USB port, which is capable of powering the camera during usage. This is a great way to have your camera last for hours. This is also a truly economic way, as you simply plug a USB power bank to the camera.
Be aware, that you may need a special splitter cable, to simultaneously run a trigger and the USB power supply through the Multi-Port connector! See here, how such a cable may look like: Combined charger and trigger cable for Sony mirrorless cameras like A6400
But to my experience with a Sony A6400, the USB port is not capable of providing sufficient power in heavy use situations. When I had the camera shoot 3000-7000 images in 1 second intervals, I ended up with a (almost) drained battery. So the camera was constantly discharging and charging the battery. The discharge rate was higher than the charging rate. This caused the camera to significantly heat up – which is highly discouraged in astrophotography!
Further more, at least the battery is set under unneccessary stress.

ProCon
– really cheap
– may last the whole night
– may be “hot plugged”
– camera may heat up
– special cable may be required
– battery stress

Option 3: Vertical Grip
The majority of the higher end and high end cameras may be equipped with a vertical grip unit. The vertical grip units are typically fitted to the battery slot instead of the battery. To power the camera, the vertical grip incorporates a tray for 2 battereries. This doubles the capacity possible. But depending on the camera, if you keep the remote trigger port constantly in focus / pre-fire mode, the camera may not switch to the second battery. So you may end up with a camera in power-safe mode and an exhausted battery as well as a fully charged one…
Further more, you have to keep in mind, that the vertical grip units are quite heavy (adding a couple 100g in weight). This may be an issue to your setup!

ProCon
– no external components
– easy to handle
– vertical grips are not quite cheap
– battery capacity only doubled
– higher weight

Option 4: External power supply
Some Sony cameras have a power in connector. This is a proprietary connector, which was already in use back in the Konica/Minolta aera. The connector is flat, with both poles on the opposite sides. On one side, there is a small bar, to prevent reverse plugging. So, technically, no big deal. Unfortunately the connectors are not available individually. But nowadays, you get really cheap power supplies with matching connectors online.
If you are a DIY person: it is really easy to build or use such a connector; Simply provide 7.2V from a mains supply, step converter or lithium batteries ;-).
To my experience, in-camera batteries are disconnected from the camera, when you plug in the external supply. So, if you plug or unplug the external supply, the camera restarts. If you leave the plug in the camera and cut the supply voltage, the camera is not operable (due to disconnected battery)

ProCon
– easy to handle
– easy to build yourself
– cheap
– perfect for studio / fixed setup
– designed for mains connection
– does not charge in-camera batteries
– disconnects in-camera battery
(no backup, if mains fails)

Option 5: Battery dummy
Dummy batteries are a great sollution for long lasting scenarios. You replace the camera battery with a plastic dummy, which has a DC plug. You simply provide 7.2-8V from any means of power supply you have. This may be a mains adapter, USB power bank with step-up adapter, a 12V car socket with step-down adapter or a lithium battery pack with 2 batteries in series. There are even some dummy batteries with included USB to 7.2V converter. But they may lack the power neccessary to drive the camera (some cameras are specified with 7.2V 2A input, which is way above the typical extended USB power scheme of 5V 2.1A.
As there are so many ways to provide the power needed, it is a very versatile option. But you have to be careful in selecting the right dummy. Some dummy units do not lock perfectly in the battery slot. So the dummy may fall out of the camera, or it disconnects. Some may have very stiff cables, which pose a lot of stress to the battery compartment lid (which is a true pain to replace!)
Hints:
– You may never want to charge the dummy battery! This may pose a high risk of damage!
– provide a well stabilized, battery-like voltage for best performance
– if the dummy disconnects or is not supplied, the camera is off immediately

ProCon
– versatile
– quite cheap
– may last several hours to days
– may disconnect
– not every dummy is well made

Summary
Depending on the situation, I choose any of these options – or even stick to replacing the batteries frequently. But my personal favorite for long lasting sessions is Option 5 in combination with a 2S 2P or 3P lithium pack (2 or 3 parallel, 2 in series). This power pack provides 7,4V straight off (no converter needed) with far more than 4 times the capacity of the stock battery. Up until now, I never ran into drained batteries, even under -10C conditions after 10 hours shooting.

NGC 3628 – Galaxy in Leo Triplet

This is the third and dimmest galaxy of the Leo Triplet. The other two galaxies M65 and M66 are quite close, but did not fit in the image. They seem to be not only close in our view. The three galaxies might interact in gravitational forces.

The dust band in front of the edge on view of the galaxy render it a very interesting and beautiful deep sky target.

Image data:
Date: 2021-04-04 – 2021-04-08
Location: Graz, Austria
Telescope: 10β€³ f/5 Newtonian with GPU corrector (1250mm focal length)
Camera: QHY183M @ -20C
Filters: Optolong RGB + Baader UV-IR-Cut
Guiding: MGEN-II with off-axis guider
Exposures:
UV-IR-Cut: 60x120s, Gain 0, Offset 15
R, G, B: 30x120s, Gain 10, Offset 15

M104 – The Sombrero Galaxy

M104 is one of the deep sky objects, I could capture during the past week of clear nights. M104 is a rather difficult target for my balcony imaging, as it stays quite low. So the influence of the air movements cauesed by the city, I am looking over, is significantly increasing stars and reducing detail in the galaxy.
Apart from detail level – this 4 hours worth of imaging goes deep enough to clearly show at least 4 small and faint galaxies around M104. The faintest being at 17.9mag.

Image data:
Date: 2021-04-04 – 2021-04-08
Location: Graz, Austria
Telescope: 10β€³ f/5 Newtonian with GPU corrector (1250mm focal length)
Camera: QHY183M @ -20C
Filters: Optolong RGB + Baader UV-IR-Cut
Guiding: MGEN-II with off-axis guider
Exposures:
UV-IR-Cut: 58x120s, Gain 0, Offset 15
R, G, B: 20x120s, Gain 10, Offset 15

Project: Messier catalog from Bortle 6 home

After several months struggle with my 10 inch Newtonian telescope, I got all configured properly. Camera, Auto-Guider, APT, etc. are well tuned to produce nice and round stars, even in several minutes long exposures.
I am unable to view or image the whole sky from my balcony setup. I may only point to an area within 80 to 220 degrees azimuth (south-east to west-south-west) and an altitude from 12 degrees to at most 70 degrees. In several occasions, this is truly a very limited view, when objects are only visible for short periods. But still, my view is facing south. So over the course of one year, the majority of the well known deep sky objects are passing by. And for the rest of the sky, I will find opportunities to drive an hour to one of my mountain observing spots with Bortle 3-4 skies πŸ™‚
Living on the northern edge of a city with a south-facing view is by far not a good combination for astronomy or astro-photography. Fortunately, the city I live in, is not too large. Therefore, my average night (if the sky is free from clouds), provides a Bortle 5-6 sky (most of the time 19.3 to 19.5 magnitues per square arc second). Visually, I have a hard time enjoying anything apart from the brightest objects. But imaging delivers really pleasing results.
During the last weeks of testing an imaging, I grew the idea to create my own Messier Object images catalog, where almost all images are recorded from this one location, with all its drawbacks. By pursuing this project, I want to show, that astronomy as well as astro-photography are still possible, even though light pollution gives us a hard time…

See the results, as I progress here: My Messier catalog from Bortle 6 suburban home

M48 and M65+M66 – finally with round stars

The past months I had trouble with my 10 inch scope. I was not able to image with nice round stars. So i kept imaging with my smaller refractor, as stars were rendered round. After some investigation and chat with fellow astronomy club members, I could nail down the cause of the elongated and triangular stars: the auto-guider as well as a too short settle time after dithering were messing up. So, to achieve the round stars everyone is after, I had to increase the settle time after dithering (otherwise, I got double-images due to the offset) as well as the guiding parameters in MGEN. My settings for off-axis guiding on 1250mm focal length are: Threshold: 0.1, Aggressivness: 100% in RA and 80% in DEC and 2×2 binning.

The first test target was M48 with 50% aggressiveness. Stars were not yet fine. The second target was M65 together with M66. Stars are fine!

Image data:
Date: 2021-03-31
Location: Graz, Austria
Telescope: 10β€³ f/5 Newtonian with GPU corrector (1250mm focal length)
Camera: QHY183M @ -20C
Filters: Optolong RGB
Guiding: MGEN-II with off-axis guider
Exposures:
M48: 83x10s L, 46x20s R, 30x20s G, 30x20s B
M65+M66: 48x60s L, 39x60s R, 32x60s G, 20x60s B

M42 with short 2 second exposures

It is amazing what modern cameras are capable of! Intreagued by learning how to improve the quality of deep sky astro photography, I stumbled upon Dr. Robin Glovers talk and essay on picking the correct exposure settings. Dr. Robin Glover is the creator of SharpCap, which is one of the best recording tools for planetary imaging.
A head full with new wisdom, I tested for myself, how true the statements according image aquisition were. Therefore I selected the core of M42 – around the trapezium – to set all parameters to. Using my 10″ f/5 newtonian telescope, I could set only a mind buggling 2 second exposure length, before saturating the 4 stars. I expected to gain a little bit of nebulosity, as the area around the trapezium is really bright. But what I could gain in post processing the 300 individual exposures is simply fantastic! Compare the 2 images attached – the nearly black one is one of the individual frames used to create the colorful result!

Image data:
Date: 2021-03-25
Location: Graz, Austria
Telescope: 10″ f/5 Newtonian with GPU corrector (1250mm focal length)
Camera: QHY183M @ -20C
Filters: Optolong RGB
Guiding: MGEN-II with off-axis guider
Exposures:
100x2s R, 100x2s G, 100x2s B

M51 and IC434/NGC2023

Saturday night, the sky was a spectacular sight. I had the chance to go out to one of my favorite places for observing. The sky was so full of stars – it was really a treat! A bit of “discomfort” posed the low temperatures, which were around -10C all night long.

As I arrived later than I hoped for, I immediately set my scope up. Scope and camera setup were up and ready for imaging soon. But then – a series of technical problems began. The scope did not fulfill GoTo commands properly. After solving this, the auto-guider could not calibrate well. I thought, it should be well enough. But upon inspecting the data back home, I had to discard more than 60% of the data due to elongated or totally ruined images. And finally, at around 2am my primary battery gave up (being only discharged 25%) due to the low temperatures. So I called it a night and went home.

The results I could gather are not as i was looking for. This is primarily due to the very low amound of data. But still, I add them here for the records…

Image data:
Date: 2021-03-06
Location: Gaberl, Austria (RGB) + Graz, Austria (H-alpha)
Telescope: 102mm f/7 APO with 0.79x flattener (equals to 564mm focal length)
Camera: QHY183C @ -20C (RGB) + QHY183M @ -30C
Filters: Baader UV-IR-Cut, Baader H-alpha
Guiding: MGEN-II with off-axis guider
Exposures:
IC434: 24x300s H-alpha, 19x60s RGB
M51: 19x60s RGB

NGC 2237 – Rosette Nebula in narrow band

Last night, I captured several subs of the Rosette Nebula (NGC 2237). Most of the subs were in H-alpha. So the O-iii and S-ii data is a bit short in signal. But hopefully, one of the next nights will be clear to add more subs πŸ™‚
The colored image is Ha = red, Oiii = green, Sii = blue. The one in black and white is the pure H-alpha image

Image data:
Date: 2021-03-02
Location: Graz, Austria
Telescope: 102mm f/7 APO with 0.79x flattener (equals to 564mm focal length)
Camera: QHY183C @ -30C
Filters: Baader H-alpha, O-iii, S-ii and IDAS LPS-D2
Guiding: MGEN-II with off-axis guider
Exposures: 20x300s H-alpha, 10x300s O-iii, 5x300s S-ii