It is a cloudy night in July on the Colorado Plateau as it has been for most of the 10 days and nights I have been in Torrey. Yesterday it rained 1.3 inches, an impressive amount in a place that averages under ten inches per year. The clouds make for a good time to post the object I acquired last month around the time of the new moon.
SV80ST set up with ring mounts holding the guide scope and guide camera on top. Telrad star finder on far side.
As I posted earlier, this past March Kirsten and I drove to California to meet with our new author Sasha Paulsen in Napa. On the way back I pulled over in Auburn to grab a cup of coffee and casually mentioned over lattes that there was a small telescope manufacturer in town called Stellarvue. Kirsten whipped out her smart phone, looked them up, called the owner Vic Maris and told him we would be over shortly. What is a guy to do but to buy a new telescope? The Stellarvue SV80ST-25SV is a refracter scope (my (Dad’s) C8 is a reflector) with an 80 mm front aperture and a 480 mm focal length making it an f-6 speed. The fully multi-coated 3 element objective lens are why it is called a triplet. The three lenses and the coatings make it apochromatic, thus APO, and low light dispersion. In some of my recent captures I used my 80mm guide scope as the camera lens and the C8 as the guide scope. I was getting bloated stars with noticeable blue halos. See my Rosette Nebula for an example. It made for a pretty but sloppy picture by current amateur standards. I liked the wide field to fit the larger nebulae and star groups into the frame but was getting tired of the compromised results. The Stellarvue seriously cleans all that up.
We ordered the telescope, a field flattener and some mounting hardware and headed for Salt Lake. A week or two later one of Vic’s techs called me to say the telescope was done and ready to ship and that it had come out with nearly perfect scores on their bench test. So much more cool than ordering a China made scope from Amazon.
Lagoon and Trifid Nebula in Sag, six hour exposure, June 18-19. 2015
The first night out with the new scope I tried to find the Elephant Trunk nebula (IC1396) but it was not an object I could see with the finder scope and I couldn’t even tell on the first photographs if I was getting it. I think I did, but it was very vague and I decided to go for something easy, a nebula viewable with the naked eye on a dark night, the Lagoon nebula and its neighbor nebula to the north, the Trifid. The nebulae are both in the constellation Sagittarius a bit above the teapot’s spout. Both are thought to be four to six thousand light years away. The Lagoon and the lower red part of the Trifid are both star forming regions. The Trifid, the upper nebula in this image, is a combination of an open cluster, an emission nebula — the red portion like the Lagoon — and a reflection nebula, the blue portion. An emission nebula is caused by ionized gasses that emit light and a reflection nebula are clouds of interstellar dust reflecting the light of the bright, young, nearby stars.
I captured this image over two nights for a total of six hours of exposure. I am a little disappointed what little difference the second night’s three hours added to the first night’s. But I remain happily dismayed by the power of the free software I use to stack the separate frames all together in one image. In this case the the software not only has to combine all the sub-frames but also has to line up the slightly different framing of the images from the first night to the second. No problem.
Sky plot from Astrobin.
I borrowed the star chart on the left from another free website called Astrobin.com. You can see the first nights capture posted on Astrobin here. The amazing magic of that site is that it takes the posted image, identifies where it is located on a star chart and names the objects contained in the image.
The six hour exposure is made up of the first night of 60 three minute sub-frames with an ISO of 1600 and the second night of 90 two minute sub-frames at 800 ISO. The table below again borrowed from Astrobin (first night data only):
On the same night I experimented with a new very wide angle 14mm lens (generous wife again) to capture a Milky Way panorama over the house. That post next time.
Thanks for looking.