# 01 Jun, 2020 14:16
I've just retired from a lifetime in newspapers and magazines. What to do with my my new life without work? stamp collecting? model railways, birdwatching? cooking? traveling (yes but not at the moment!)
But what I want to do first is try is astrophotography. But being under lockdown gives a problem - I can't see the north star from my balcony. So I can't use a tracking mount, or can I?
I'm hoping that I can learn from this community about how to use my camera, a Sony RX10iv for shooting the planets. Starting with Saturn… let's see if I can do it with just a sturdy tripod and no mount!
The first problem I see could be France! No offence mes amis, but the light across the English Channel (La Manche) coming from Calais is very strong. But then Dover docks is also lit up as if were daytime! Well we'll see…
# 01 Jun, 2020 14:25
Congratulations on retirement, and welcome to Astrobin from Southern California.|
Seems to moon and planets are a good place to start, they were for me.
# 04 Jun, 2020 22:10
Polar alignment might be a problem if you can't see Polaris at the moment. What sort of mount have you got, as with some mounts it is possible to PA without seeing the pole star.|
The other problem I see is your camera. I am a bit out of date with using a DSLR, so some-one else might need to help with this, but when I was using one, the planets were a bit too small and bright for a DSLR.
What you will be able to get though is great shots of the milky way with your camera lens, depending on the LP.
One thing you can easily do during lockdown, is star trails, just point you camera towards the North, and don;t track at all, and take a series of long exposures, probably a minute or so long and then stack them together to get a star trailed image.
DSLRs are normally better for doing Deep Sky Imaging, but for that you need long exposure, and to be able to see the pole, but you could start simple until you can get out of lockdown, and do some "say 15 sec exposures and stack them together in stacking software - DSS Deep Sky Stacker is free and the one most people use when they start. This will at least get you going while you are confined to barracks.
# 04 Jun, 2020 23:39
Thanks for that very comprehensive reply. It is really helpful.
I don’t have a mount yet so it is interesting to know that they are available without pole star reliance.
My computer is a Mac I will have to find a different stacker, Siril seems good.
You are right about planets being too small and bright with DSLR. Even though my lens zooms optically to 600mm it doesn’t really get the planets. However, I have a shot of Jupiter with moons. And one of Saturn where if you squint, you can just make out it’s ring!!
# 05 Jun, 2020 17:16
planets are not too bright or small for modern DSLR. The brightness can be adjusted by using low ISO number and short exposure time.
The size off the planets in your images depends solely on the focal length of your lens/telescope. You need quite a long focal length to take decent shots of planets.
why is the lockdown keeping you from finding a good spot with view on Polaris? Social distancing isn’t really relevant in astrophotography, which most people do on their own.
# 06 Jun, 2020 15:03
|Well I will try again. My Focal length is 24–600 mm and Max aperture F2.4–4. The biggest problem I find with this camera is focus. I have on a sturdy Manfrotto tripod and I use an electronic remote|
# 06 Jun, 2020 17:47
|Glad you are here brother, and we appreciate your work in media. I'll keep a look out for your new work!|
# 08 Jun, 2020 12:29
For halfway decent images of the gas planets you need a reflecting-type telescope with at least 1500mm native focal length or less with a barlow lens. Next, a dedicated CMOS camera, such as the ASI120MC-S or ASI290MC (lowest price tag). Plus, a mount capable of carrying the payload. All essential capture and processing software is offered for free.
Since both Jupiter and Saturn rotate fast (and further to combat inaccurate mount tracking), you need to look at shortest possible exposures to avoid image smearing. Consequently, a telescope with a fast focal ratio, say F5. A Newtonian appears to be the best choice keeping the budget low, but can get very heavy with increasing aperture. My choice of a 6-inch Newtonian was a compromise between aperture and weight, the latter having a big impact on the cost for a mount. More aperture at less weight and shorter tube length is provided by Schmidt-Cassegrain telescopes, such as 8-inch F10 types with 2000mm focal length which is great for the planets. The Newtonian is also ideal for imaging deepsky objects with a DSLR, however, it needs to be collimated prior to every session.
The Schmidt-Cassegrain is okay for deepsky, but requires much longer exposure times and autoguiding (requiring an additional guide scope and CMOS camera).
About Imaging Camera
A DSLR is not suitable for planetary imaging. A dedicated CMOS camera with a small sensor is essential. Monochrome cameras are more sensitive and sharper than color cameras, the latter relieving need for a color filter wheel and quadruple exposures. Actually, the difference is not worth the hassle with filters in that I went for a color camera.
Provided you are sure that you won't give up your new hobby and swap it for knitting, it would be wise to allocate a generous budget to an equatorial mount. A sturdy mount that accurately tracks is the key to good images because you will be working with a long focal length, thus high magnification. Every mount is specified with a maximum payload. For best results consider a mount with a payload twice that of your gear. Payload capacity also depends on the length of the telescope tube and its center of gravity. Since Polaris is out of your view, the equatorial mount should be equipped with a port for PC control. Sorry, I do not recall what exactly is required but with certain software and a CMOS camera it is possible to polar align a mount without a visual line to Polaris. There are also mounts that can be used in both, equatorial and "AltAz" mode, the latter not requiring polar alignment, such as the Sky-Watcher AZ-EQ5GT.
I used to live in Tokyo (now in Okinawa) and can tell you a thing or two about nights as bright as in daylight. Perhaps you have the option of moving to a darker site. A perfectly dark site is not too relevant for imaging the bright moon and bright planets, but good seeing (steady and transparent atmosphere) absolutely is. Imaging nebulae and galaxies under a light flooded sky is a pain in the neck without extra accessories. For the cost of a good filter set you can rent a truck,
round up a few friends and move flats, well, after the lock-down.
Before you spend money on gear, please browse AstroBin for images taken with various scopes and cameras to get an idea of what you can expect to achieve. This was my first ever image with a 6-inch Newtonian and an ASI120MC-S camera:
With more experience in both, acquisition and post-processing, moreover, with better seeing, you can obtain more details.
Anyway, welcome to the sky gang :-)
# 08 Jun, 2020 14:24
|Robert, Thank you for leaving such a welcoming and helpful post there. It is really interesting. I have to research now.|
# 12 Jun, 2020 20:49
|Welcome to the community on here. A word on your light pollution problem - it isn't, and many of us would give our right arm to have the Channel between us and the next light. I live between Birmingham International Airport, the main Jaguar LAnd Rover factory, Birmingham city/W Mids conurbation, and sit in Solihull a town of 100,000 inhabitants - on a dark night I can read a book! I can still get images that are pleasing to my eye with a basic set up, it just takes longer and some objects are going to very hard or impossible, but 1000's aren't so still plenty to choose from. So enjoy what would be to me inky blackness in Dover.|
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