Shooting from Bortle 8 skies with an f/5 scope means exposures get blown out or go white fairly quickly. Shooting long exposures is doable but with my skies and setup I’d greatly benefit by using a light pollution filter. But what type of filter would work best for my rig a 2″ round or clip-in, etc. What’s available for my older Nikon D5100 DSLR and where would the optimum location for a filter reside in my light train?
With these questions in mind I ventured to find out. My first stop? A quick scan of the owner’s manual for my Meade Series 6000 70mm Quad APO Astrograph but surprisingly this revealed no information at all. There is this in the owner’s manual:
Not much help really and the “picture” mentioned above is not actually on the whopping 2 page owner’s manual. So after searching online for information on adding a filter to my specific scope and even calling Meade Customer Service for assistance; I got nowhere. I felt sure that a filter could be added I was just seeking assistance with the best approach.
The Test
I didn’t have a 2″ filter so I bought an inexpensive 2″ Solomark Moon & Sky Glow filter for $20 bucks off Amazon mainly as something to test with before taking the plunge and buying a high dollar LPS imaging filter. I’m glad I decided on that route. I very quickly found out that the 2″ filter did fit nicely between the 48mm to 42mm adapter that is used to connect the DSLR to the telescope. The line up goes like this: DSLR, Nikon T-Ring adapter, 48mm to 42mm adapter, Moon & Sky Glow Filter, telescope. Success! Not quite. Adding the filter at this point in the light train increased the distance that the camera was from the back of the scope. By pushing the DSLR back slightly I was then unable to achieve focus. The focal point with this telescope is very close to the end of the scope with the focuser almost fully racked in. There is hardly any travel to work with. Back to the drawing board.
Tomorrow morning (Monday, February 17, 2020) be on the look out for a nice planetary alignment. If you are up early tomorrow morning and have a good view of the southeastern sky be sure to check out Saturn, Jupiter, Mars and the Moon as they line up in that order.
President’s Day Planetary Alignment
Additionally, for those in the DFW area the International Space Station will be making a fairly bright pass (-0.6 mag) right through this line up! In fact, the space station should pass between Saturn and Jupiter around 6:37 a.m. See the screen shot above that I made from Stellarium for more information regarding the alignment and passing of the ISS through them on Monday, February 17th 2020.
You might be wondering why I haven’t jumped on the Betelgeuse “dimming” bandwagon and yelled from the roof top “The sky is falling!” err sorry, “Betelgeuse is about to go supernova!” Well, I decided to tap the brakes and take a wait and see approach. At least for a little bit. Often these types of reports travel at the speed of light only to fizzle out leaving people to later ask “Hey, whatever became of that star that they said dimmed a little bit, and might even explode?”
The reality is Betelgeuse is destined to go supernova and astronomically speaking it’s due to happen pretty soon. Betelgeuse is a red supergiant star and starting back in October of last year the star noticeably dimmed in brightness, thus far by a factor of 2.5 from magnitude +0.5 to +1.5. This is not totally out of the realm of possibility since Betelgeuse is a variable star whose brightness fluctuates from +0.0 to +1.3 but it was enough for astronomers to sit up and take notice.
The constellation Orion (The Hunter) with Betelgeuse at upper left.
The star is 650 to 700 light years from Earth, the second brightest star in the constellation Orion behind Rigel and is the 11th brightest star in the night sky. As luck would have it Orion is perfectly placed these February nights for you to step out after dark, and if you are in the U.S., face south. You’ll find Orion fairly high in the southeast and crossing the meridian around 9 p.m.
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