Proper Session with the Explorer 150PDS

[PeterC65]

This was the first proper session with the new Explorer 150PDS. There was some moonlight at the start but the Moon quickly disappeared behind the trees. Throughout the session the sky was fairly bright though, and I could easily see what I was doing.

I checked the collimation with the laser collimator at the start of the session after the scope had been mounted and adjusted the primary mirror slightly.

I aligned the mount with Arcturus and Vega, using the Brightest Star method for the first time. This came up with two sensible objects with which to align within the south east quadrant of sky. It seems a better method than the 2-Star method.

I had to rotate the optical tube in the rings during the session to point the eyepiece more towards the vertical to make viewing easier (less stooping down). The eyepiece position is now quite comfortable at all altitudes but it is harder to keep still than when seated and harder to observe an object for longer periods.

The SynScan AZ GOTO mount seems to be coping well with this slightly too large scope. It takes a little longer for the wobble to die away but not so much that it's an issue, and the frequency of he wobble is slow enough for me to follow objects with my eye while focusing on them which is actually an advantage!

M13

Found with the ES 24mm with which it is clearly visible, then framed properly with the ES 6.7mm. It looks like a bright smudge, with a brighter centre and some of the constituent stars just visible when looking directly at it and certainly visible with averted vision.

M3

Found with the ES 24mm and framed better this time with the ES 4.7mm. Similar in appearance to M13.

M5

Found with the ES 24mm and framed with the ES 6.7mm. Fainter than both M13 and M3 so the constituent stars could only just be seen with averted vision.

M53

Found with the ES 24mm but faint so it needed the ES 8.8mm for framing. It is very faint and small, just a smudge with no sign of the constituent stars. There are two close unnamed stars very nearby which made the view more interesting, like a pair of cats eyes staring out of the dark.

M94

Found with the ES 24mm but faint so it needed the ES 8.8mm for framing. Just a small faint smudge with no detail of the galaxy. It was quite close to the Moon and the sky was relatively bright so not the best night to observe this galaxy.

M66 / M65 / NGC3628 Leo Triplet

I spent some time trying to find this with the ES 24mm, the ES 14mm and the new BCP 32mm. There is an arrow head of three stars with a fourth brighter star at the tail of the arrow that points to M66. I could just about convince myself that I could see the three galaxies with averted vision when slewing the scope but I’m far from sure. The sky may have been too bright as the Leo Triplet always seems hard to see. Adjusting the scope in its tube rings may also have upset the alignment slightly so I was less sure that I was pointing at the right thing (when it was something I couldn’t see).

M81 / M82

Always reliable and both galaxies were nicely framed with the ES 14mm. M81 was clearly more elliptical and M82 clearly more linear. The galaxies could be seen individually with the ES 4.7mm so like the refractor, the Explorer 150PDS lets me see both the two together and separately which is nice.

I also tried the SW 28mm 2” on this target which is the first time I’ve used this eyepiece. The view was similar to the ES 24mm and the quality not quite as good. I don’t see any benefit of using the 2” eyepiece over the ES 24mm, and it requires the focus tubes to be rearranged.

M27

Surprisingly easy to find, so the alignment can’t have been that far off. The ES 8.8mm with the UHC filter was best. The UHC filter made a huge difference, blackening the background sky and really bringing out the planetary nebula. It has a definite elliptical shape with just a hint of the dumbbells. Quite a nice target and I spent a while observing it.

I tried the new OII filter which just darkened the sky (and everything else) even more. It was useable with the ES 24mm but then the nebula was small and I couldn’t make out its shape. This filter clearly needs a big exit pupil and so is probably only useable for larger nebulae (which to be fair is what I bought it for).

M57

Emboldened by M27, I tried for the much smaller M57. It was hard to find and I only just noticed it while slewing around the area with the ES 14mm as a blob just slightly larger than a star. It looks best with the ES 4.7mm and no filter. As it’s small it needs high magnification so the exit pupil is small and there just isn’t enough light for even the UHC filter. It looks like a small ring which is definitely less bright at its centre.

I tried the ES 3mm but it was hard to see anything, and then the ES 6.7mm with the x2.25 Barlow which was much better but probably too much magnification, although it did make the ring structure clearly visible. The ES 6.7mm and Barlow combination has a much wider field of view than the ES 3mm and is easier on the eye.

[Kon]

Excellent report and some very good targets.