Saturday Session

[Paul81]

All observations using AA6RC at F4.5, using SX Lodestar-M, Astronomik CLS filter and Lodestar Live V0.10. All images are as seen at the telescope, no post processing has been applied (stacking performed live). All images have had live-view dark frame subtraction applied, the darks where collected as I was setting up my mount and waiting for darkness to fall.

 

M52

 

6x30s median stacked. The open cluster M52 contains around 193 stars and is thought to be some 35 million years old. The cluster resides in the constellation of Cassiopeia nearby to the next target for the night so served as a good ‘warm up’…

 

 

NGC7635 / Caldwell 11 - The Bubble Nebula

 

The Bubble is a HII emission nebula, whereby the bubble is created by the stellar wind of the massive very hot central star. This process is also causing the whole nebula to expand and glow.

 

Single 30s exposures show the nebula well, but the bubble shape became much more apparent with each exposure. Switching to sum stacking, and setting a wide display dynamic range, it was fun to let each exposure come in and see the bubble start to appear and take shape. Darkening the background also helped to bring out the bubble shape, at the expense of the background nebulosity. I am not sure which version I prefer, the sum or median stacked. I think each one highlights the bubble in a different way. This is an object I will return to with a different filter(s).

 

 

NGC7023 / Caldwell 4 - The Iris Nebula

 

The Iris Nebula is a reflection nebula in the constellation of Cepheus, whereby NGC7023 is actually the cluster of stars that reside at the centre of the nebulosity. 10x30s median stacked exposures show the faint whips of the outer parts of the nebula, which are mostly dark brown dust (in deep astrophotos). The inner part of the nebula is very bright, I am thinking this is another object that may well benefit from the forthcoming non-linear display dynamic range controls in LL, in that the bright central portion can be preserved whilst highlighting the fainter whips of nebulosity surrounding the bright centre.

 

 

M108

 

Time to go galaxy hunting. Firstly some familiar faces in Ursa Major. M108 is a barred spiral galaxy which is seen pretty much edge on from Earth. The galaxy is a member of the virgo supercluster, has an active galactic nucleus and is thought to be around 45 MLY from Earth. I tried both 30s and 45s exposures, deciding that the 6x45s median stacked image gave the best detail. Some of the dust lanes in the bright centre of the galaxy can easily be seen. Visually, this galaxy is a vague smudge from my back garden, with little or no detail visible. Electronic observation transforms it completely!

 

 

M82

 

M82 is a starburst galaxy and is part of the M81 group, and is in the process of merging with M81 which is the primary cause of the starburst activity. The galaxy is around 12 MLY away, and made headlines earlier in the year due to the type 1a supernova observed in the galaxy (see one of my previous posts for an image - and tons of others online). Very little remains of the supernova bright spot now. 45s exposures were used for a total of 8x45s median stacked to try and spot some of the fainter outer parts of the galaxy.

 

 

 

M15

 

A quick pitstop to the globular cluster M15 in the constellation of Pegasus. This was party to re-sync my mount as slewing to different parts of the sky often shows inaccuracies in the GOTO (likely due to the fact I do not pay much attention to levelling the mount). It would have been rude not to have spent some time on such a lovely globular though, so here it is 3x30s median stacked. I would have normally used 20s exposures, but I only captured darks for 30s and 45s, and I was starting to get cold so didn’t really want to wait around the extra time to grab 20s darks. M15 is quite a fascinating globular, being one of the most compact and is home to 100,000+ stars, some of which are variable and pulsars. M15 also contains a planetary nebula, which was the first discovered (inside a globular cluster). The cluster itself is some 12 billion years old.

 

 

NGC7331 / Caldwell 30

 

Back to galaxy hunting. NGC7331 is a spiral galaxy in Pegasus and is very similar to our own Milky Way. It lies some 40 MLY away. Some of the spiral structure is visible in the 20x30s median stacked image, and this structure became more visible during the period of observation. Tuning the white level, several other galaxies can be seen in the image (see annotated), particularly NGC 7335, NGC 7336  and NGC 7337. A fascinating image, which is probably why I kept looking at it for 10 or so minutes. I think this has fuelled a galaxy cluster addiction (although some of Martins images had already got me hooked).

 

 

Stephan’s Quintet / HGC 92

 

Onto the last object of the evening, Stephan’s Quintet, a grouping of five galaxies in Pegasus. Four of the galaxies form a compact galaxy group which was the first ever discovered. The bright foreground galaxy (NGC7320) is not part of the group, but is just visually in the line of sight. This spiral galaxy is around 40 MLY away. The four interacting galaxies are some 300 MLY away. The four galaxies are undergoing merger, and one of them is falling into the centre of the group at several million miles per hour. This naturally causes huge shockwaves (bigger than the Milky Way), evidence of which is in very deep professional multi-spectrum images. One of the galaxies looks like evil eyes to me. Again I find this a fascinating image, and thinking about the universe in such grand scales. I got quite lost in imagination which is one reason the image here is 12x45s median stacked.

 

 

At this point I was frozen so called it a night, but it was a very enjoyable session and I shall be doing more homework to find more amazing galaxy clusters to hunt down. I also have a lot of test data to work on the new display processing controls upcoming in the next release of LL - the main issue here being time to work on it!

[Martin Meredith]

I really enjoyed reading this -- excellent images and write-up, just the job for a Sunday morning astro-fix! Sounds like a great session.

Observing + imagination is a powerful combination. Getting that bit of extra detail from the sensor (compared to visual) I find catalyses the imagination, even though pure visual typically requires more imagination...).

Your Bubble Nebula makes a convincing case for experimenting with stacking/exposure/histogram settings to tease out faint details. Doing all of this live makes it seem more like conventional observing too.

Lovely image of Stephan's Quintet -- clear galaxy morphology.

Two hours is a typical session length for me (I tell myself it is mainly determined by laptop battery but it usually coincides with getting too cold from immobility). You wouldn't believe it is August with the night-time temperatures we're having in the UK.

Martin

[RobertI]

Really good haul of interesting objects. I particularly like the 'evil eyes'!

[HiloDon]

Really great stuff, Paul! Everyone is showing how far reaching the new Lodestars are with your LL s/w. I had a great night with them last night until the clouds moved in. The stacking feature has expanded the Lodestar capability while improving quality. Thanks again for all of your efforts.

[nytecam]

Excellent work Paul - images and text - a lot of work there on both counts - well done - particularly like Stephan's Quintet [that I also shot last night] and the Bubble Neb

[Paul81]

Thank you all!

I have definitely found an observing routine I have been enjoying recently with the Lodestar and LL, its good to play around with the image to see what you can see in the objects and I tend to just let it capture at least 5 or 6 frames before I pay too much attention - in that time I am online reading up on the object in question to learn more about it. That is something I never really do visually - it is more about finding the object than really understanding what it is I was looking at. I also make notes whilst observing (which I then 'tart up' the next day and that forms the bulk of my post) - again something I never do visually.

I still have a hankering for visual though. I need to get Robertl's suggestion of a night mode in the program so the laptop screen doesn't destroy night adaption (or I guess a filter over the screen?). That way I can combine LL and visual for another dimension to observing. Hmm.. wonder if the Az-Eq6GT will take the RC and VX10 at the same time...