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Stu

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  1. Stu

    Double shadow transit

    By Stu,

    Just an example of a typical quick observing session for me, trying to fit it in around 'life'! I have a baby due in a couple of weeks so we are manically preparing the house and nursery for the arrival.
    I set the TV76 and PST up in the garden early on Sunday morning, and during rests from painting skirting boards had some lovely white light and Ha views. My mini giro rig is working very well now, more compact with the shorter CW bar and L bracket.
    During breaks from assembling a flat pack IKEA wardrobe (AAAARRRRGGGGGHHHH), I realised there was a double shadow transit on Jupiter last night so thought I would chance my arm at a little evening session too. I popped the PST and Herschel wedge away, put the longer CW bar on and away we went.
    It's amazing the detail visible with such a small scope. Earlier on GRS was clearly visible, with nice detail around where it nestles into the belt, whilst the Ganymede shadow transit was stunningly clear, really jet black. Nice details in the other belt too in moments of good seeing.
    I tried a variety of EPs, and settled in the 3.7 Ethos earlier on (x137) when the seeing was better. Later on the 4 mm radian gave sharper views at x120.
    I watched the double shadow transit at its mid point, Io's shadow smaller and less obvious but still very clear. That's a first for me I think. My last view was as Ganymede's shadow was about to exit the disk, but the seeing had dropped off by then.
    Packed away very quickly and off to bed. It's great to be able to view these events with minimum hassle. I know the detail is not what you would get in a larger scope, but if the choice is that or nothing, I'll take the small scope option every time.
    Cheers,
    Stu
  2. Stu

    Televue Twins

    By Stu,

    Left the tripod out and switched things around to add the Genesis alongside the 76 for a bit of side by side on Jupiter and a few other favourites. There is no adjustment horizontally so they are not quite lined up, but near enough. Will try another configuration to see if I can sort that.
    Jupiter was looking very nice, a reasonable amount of detail visible. I could just see the GRS coming round the corner but unfortunately it clouded over before it transited. Some nice detail in the belts, and what was obviously a shadow transit centre towards the bottom, couldn't see any sign of Callisto though. This detail was visible in both scopes. I actually am preferring the view through the 76 at the moment, particularly at higher powers. I think the collimation is out on the Genesis still and star shapes are nicer, with less (no) CA in the 76. That said, I bought the Genesis for its flat, widefield views and it does those wonderfully. I shall have another tweak again, or perhaps consider getting it somewhere for a service.
    M42 looked lovely in both scopes, nice sharp trapezium and nice mottling detail in the nebulae. The 'wings' looked very well defined despite the LP and no filters.
    Only other thing I viewed was the double cluster. Beautiful in both, but again just that bit sharper in the 76. Really wonderful tiny stars peppering the view at the limit of visibility, one of my favourite things to view.
    Clouded over and have now packed up. This was an unexpected session, forecast was not good so was nice to see the shadow transit, shame about GRS.
    Stu
  3. Stu

    Small refractors, urban skies

    By Stu,

    I thought I would start this off as a way of logging what is possible with a small refractor under poor, urban skies.
    By poor, what do I mean? Well I live a few miles south of Heathrow, which basically wipes out most things to the north. I am on the edge of Walton on Thames, and have a relatively decent southern view over fields, but there are houses in the way so the seeing is often mixed.
    My NELM is normally around 4.2 to 4.5 but can be better or much worse depending on the transparency. Background sky brightness is around 18 to 18.5 in the best direction, so many galaxies are a challenge.
    For reasons of convenience, and because I love them, I have a collection of smallish, but decent quality refractors which are my most commonly used scopes.
    TV76
    TV Genesis
    Astrotech 106mm EDT
    The first two are small and light enough to use on a mini giro on an Induro AT413 tripod, very quick to set up and pack down. The triplet is heavier and I normally use that on an EQ6 tripod, previously with a giro but will use on the mini until it sells!
    So, just a quick comment on last night. I had been playing with the collimation on the Genesis so thought I would give it a try out. I had a quick half hour under some nice skies before going out. I was just testing really, but had nice views of Jupiter with GRS, M45 and M42. This scope is lovely for flat, widefield views; at 500mm focal length, a 21mm ethos gives a 4.2 degree field of view, a 17mm gives 3.4. Under a dark sky (which I have yet to get it under!) objects like the Veil and NA nebula should be lovely, particularly with Lumicon UHC filter.
    I will try to post up about what is achievable/visible in these scopes under my skies as a reference for people.
    One example of the challenges.... Many of you will have seen the SN in M82 which is a relatively easy target under reasonable skies or with a little more aperture. With my 106, I just about managed it using averted vision. It was probably one of the hardest things I have managed to observe. On another occasion with my 12", it was trivially easy to see! Just finding M82 under light polluted skies can be a challenge in itself!
    I tried to see comet Panstarrs (whichever one it was ....), and eventually concluded that it was invisible from my skies. I tried scope and binoculars, but it was hopeless. I visited a relative in Bakewell and found it within seconds in the binoculars.
    Background sky brightness and surface brightness of objects are key to understanding what is visible and what is not. I will confess to a little frustration, seeing posts on here discussing light polluted skies, followed by reports I can only dream of from home. I think there is a big difference between local light pollution in the form of nearby streetlights and houses, vs the horrible orange grey glow which hangs over the larger cities. If your sky is fundamentally ok, then it is possible to block out local annoyances. The other way round there is nothing you can do.
    So, my aim is to focus on what can be achieved with limited aperture kit under poor skies, how to identify good targets (ie visible!) and a description of what I have seen.
    The answer generally at the moment is 'very little cos it's cloudy', but I shall be back when it clears.
    Cheers,
    Stu
  4. Stu

    Out in the sunshine

    By Stu,

    Despite being on decorating duty today, I managed to pop the scopes out this afternoon for a quick look at the sun. I have acquired a couple of bits to make my mini giro setup a little more compact, namely a 13cm counterweight bar (Teleskop Service) and smaller L-bracket (365 Astronomy), and was just wanting to try them out.
    All worked well, the mount is still well balanced and moves smoothly. It's quite easy to align the PST and 76 so that they both point at the sun, avoiding constant movement and making comparisons between Ha and white light views very easy.
    The photos show the before and after kit shot, much better now. The only other things I might do is replace the az tightening knob with something a little bigger, that would make fine adjustment of tension easier.
    The views through the Herschel Wedge in the 76 are really lovely, granulation nicely visible, and some amazing detail in the Active Regions. The sketches on the forum are very good representations. PST view was a little quieter to me today, no particularly big proms around but stil some nice views.
    This kit is very quick to setup and gives really satisfying results.
    Stu
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