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First light with a SW 150PL


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I took delivery of my first telescope - a Skywatcher Explorer 150PL Newtonian reflector with EQ3-2 mount - about 10 days ago. Never having owned a real scope before it was a little daunting, but also quite exciting.

It was all safely packaged - two large boxes, each with a snugly fitting box inside. The longer box contained the OTA, suspended by three rings of expanded polystyrene and fully assembled (although I had to detach the tube rings to remove the sheet of tissue paper protecting the main tube). The other box contained lots of smaller boxes, neatly sized to completely fill the available space. One large box had the tripod while others contained the mount, counter-balance weights, eyepieces and finder scope.

I was somewhat apprehensive about putting all this expensive equipment together (ok, so it's an order of magnitude less dear than many scope, but for me it was a significant price to pay). But I needn't have worried. Assembly was remarkably straightforward even though the instruction book didn't explain everything (yes, I know, men aren't supposed to read instructions, but I wasn't taking any chances).

Unfortunately, as you are all well aware, the weather in the UK has not been very kind to us recently and it was a couple of days before I managed to get something to point it at. I had set up the finder scope during the day, using the furthest object I could easily see and identify - the top of a tree some 100 yards away (my garden is surrounded by short trees), but this proved accurate enough for location objects a few million miles further away.

On Sunday the 13th I had a very brief opportunity to peek through a couple of gaps in the clouds. I only had time to look using the lowest magnification (x48) although this was enough to glimpse Jupiter which had thoughtfully placed itself directly behind the hole in the clouds. I couldn't make out any significant detail, but I was delighted to see four bright dots in a line - something that I'm sure brings excitement to anyone who has observed the Jovian giant. That was all I had time for before the gap closed and I felt once more that I had been transported to Krikkit.

It was another week before I was able to get another chance to use the scope in anger, but it was well worth the wait. The afternoon of the 20th December was clear and crisp, and there was no sign of the evening clouds that had marred many of the preceding evenings. I started early and set the scope up as soon as the sun went down. hoping to get some views of the waxing moon. I wasn't to be disappointed.

As it was still quite light it was easy enough to set things up. Placing the tripod (unextended) on the hard snow and using an old compass which I'd used when hiking across Dartmoor in my youth (the darkest skies I've ever seen in England), I pointed the "N" leg as close to North as I could. The small bubble level built into the tripod helped me to get things on an even keel. I'd already set the altitude adjustment to approximately 51 degrees (although once it got dark I fine tuned it to line up with Polaris a little better).

Pointing the scope at the moon (it takes a few moments to get used to swinging the tube around on an equatorial mount) I was rewarded ith a magnificent sight. Although the sky was still quite light I got a great view of the thin crescent of illuminated lunar surface, with fantastic detail along the terminator. At x48 the disc seemed to fill the eyepiece. I had bought a Meade ND96 moon filter, but this was not necessary as the comparative brightness was not that great and it was too early for any night vision to be affected.

This was a great opportunity for me to try out the other eyepieces for the first time, so first I added in the x2 Barlow, had another "wow" moment, next the 10mm EP on its own ("whoo") and finally added the Barlow again (x240 - "gasp"). I called my 13 year old out to have a look and he was suitably impressed. Even my cynical wife seemed to think I had actually got something that works for the 200 or so notes I'd shelled out for the scope.

Although it still seemed quite light, I could just make out the small bright dot of Jupiter, 20 degrees or so to the South of the Moon. Time to peer further into the solar system. A few seconds later I had the gas giant in my sights (easily located using the red-dot finder I'd acquired a couple of weeks earlier on eBay, following a couple of recommendations). Given how light it still was, and how low Jupiter was in the sky, and that the scope had been outside for less than 20 minutes, I was surprised how good a view rewarded me. Even to my untrained eye some banding was clearly visible across the planet and two of the four main moons were clearly in view (Io and Ganymede according to StarmapPro). To the novice (me) it was surprising how quickly Jupiter moved across the field of view (and out of it). I have also bought dual-axis motors for the scope - this are going to be fitted very soon.

It was then time to eat, so I left the 150PL in the garden to continue cooling while I went inside to warm up and have a hot meal.

An hour later, with woolly hat, thick coat and lots of enthusiasm, I ventured outside again. The EP had fogged over, but after a careful wipe this was cleared and I could start viewing again.

I spent the next few hours finding my way around the December sky, trying to view things of interest. M42 in Orion was the obvious first target, then Betelguese, Rigel and Bellatrix, admiring the different colours of these stars. I tried (but failed) to locate the Triangulum galaxy, M33 (more eye and brain training required) but had a magnificent view of the Pleiades. I also took in what I think was the Hyades and several of the brighter objects in the sky.

Despite the cold I was getting used to swinging the scope around the mount and using the RDF to locate things. I frequently found myself loosening the tube rings to rotate the eyepiece to a more comfortable and practical position. I was becoming more and more aware of the ice that was building up on the outside of the main tube.

By midnight Mars was high enough over the trees to get a good view, and by then I was nearly as cold as my scope. A little wary of what best to do with it, I went back inside take the instrument with me. Looking down the tube I could see that the main mirror was completely misted over - I'm not sure if this had happened whilst outside, or was a consequence of binging it indoors. I left removed the EPs and rotated the tube so that it was horizontal - the ice on the outside had quickly melted, and I didn't want any melting ice on the inside to foul the mirror. I left everything uncovered until the morning - with the tube and focuser open to the air, and left the protective caps off the eyepieces. I hope this was the right thing to do, although all looked fine afterwards.

All in all it was a great first session. I've learned quite a bit about my scope and learned that I still have a lot more to learn. Celestial navigation is going to be a steep learning curve, but with Turn Left at Orion on my Christmas list I'm hoping to have a good guide to help me.

Thank-you to everyone who recommended the 150PL, and to those who suggested the alternatives. I can see I'm going to be spending many more cold evenings in wonderment.

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Congratulations on what sounds like a successful 1st light !.

Don't worry about the misting over of the mirrors when the scope comes in from the cold - that's quite normal. With eyepieces, I usuallly keep mine warmer than the scope to stop them misting - I have a foam lined case for mine which keeps them a little warmer. If things do mist over do try and resist the instinct to wipe the optics - it's much better to let them de-mist themselves, even the eyepieces.

M33 is quite a challenge as it's a face on galaxy, quite large but pretty faint and spread out. The magnitude given for it is the integrated magnitiude so it looks a tempting 1st DSO target but it's a bit misleading.

Hope you get lots more great nights at the eyepiece :D


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Great first light report and its wonderful to see a beginner get so excited. Its a great scope and I'm sure you will get lots more great views with it.

The 6" reflector used to be the mainstay of amateur astronomers back in the 70s and 80s so its a very solid bit of kit in its capabilities.

Its great to see you getting the hang of it all so fast as well.

As John says dont worry about the kisting. All scopes get wet and cold when outside and refelectors do mist up and sometimes get water streaks on the main mirror. Its nothing to wrry about. Just let it warm up inside.

Like John I keep my EPs in a foam case when not in use to keep them dew and mist free. You can also keep them in your pocket to keep them warm and dew free.

Congrats though on what was obviously a great night for you and thanks for writing it up.

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