Jupiter, Trapezium and the effects of power.

[alan potts]

Report from 7^th January.

Scope 180mm Sky-Watcher Maksutov.

I have had this scope now for a good few months and I have to say it is rather under-used compared with some of my others, I did not fall in love with it when I got it and now sometimes wonder why I bought it in the first place.

But I have it so I should use it.

Jupiter.

I had a few eyepieces in hand and pocket; 17mm Ethos 18mm Kasai 20mm Nagler and 14mm Delos.

I started out with Jupiter in a part of the sky where I seem to get an unusual amount of air turbulence, why there I am not sure, it could be the river which at the moment is about 6 inches deep but 80 yards wide.

Starting with the Nagler which is as good a place as any, this gives a power of X135, a little on the low side but I was hoping seeing would improve as Jupiter climbed higher in the sky, which seemed dark even though there was a first quarter Moon in the sky, but a good distance away. The disc was lovely and sharp with the occasional shimmer, caused by heat and smoke from my own wood burner heating or something else. This early there were just the two main belts on show with some clear shading in both polar regions. Also I could see that later on there would be two of the moons crossing the main planet disc, something that was worth staying up for just so long as the fog did not form early. Fog is something that has been a pain this last few weeks, the air is very wet and this has a direct effect on seeing conditions as well as cutting short observing sessions. For the moment I will leave Jupiter to clear the tree and hopefully allow me a better look at the detail a little later on, there is no better time than the present to observe this body as it is only just passed opposition.

Messier 42 and the Trapezium

I moved over to Messier 42 for a crack at the Trapezium and in particular the ‘E’ and ‘F’ components of this well viewed nebula. There is something that I find rather odd about this group and that is the best power to see these is around X120 though it does vary a bit from scope to scope. The 180mm Mak is a scope that is something of a specialist with double stars, or so I am lead to believe. The other thing is many site members use very large powers to split close doubles this group seems to defy all logic when it comes to magnification.

Feeling the 20mm Nagler and its X135 was a good place to start I set about cracking these doubles. Now conditions were at best, average but it was very clear, you could feel the moisture in the air and even touch it as it was starting to condense on a few things, like the tube of the scope and the 35mm Panoptic which I had carelessly left out. With 20 minutes of changing eyes and trying averted everything, nothing not a sight of either double, yes you could see they were there but I want to see a gap and you can with both, even in a smaller instrument went the weather is playing ball. This was the time to go for another eyepiece, enter the 26mm Nagler from a warm house and bang goes my night eyes for a few minutes, never a great problem when there is a Moon. The 26mm giving a magnification of X103 immediately cracked the case; there they were ‘E’ and ‘F’ and clean and clear to see. How strange it is that reducing the magnification by a fairly small X32 can get a completely different result and make the night worth while.

Jupiter revisited.

Jupiter was now in a much better place in the sky and it was back to the 20mm Nagler to see if it was showing me more. The two moons were now getting even closer to the main disc and looked rather nice but i knew then there was not enough time, I could tell that things were going to be curtailed by the weather. Though still very clear I know how quickly the fog builds here and 10 minutes will be all it takes.

Jupiter was now showing tantalizing glimpses of two belts either side of the main equatorial belts and some detail in between these, as well as a much better defined polar regions, the only time I had seen it this good was with my larger 12 inch LX. I made the move up in power to the 17mm Ethos (X158) and boy that really lit the blue touch paper, the planet was clearly showing 6 belts and two clear polar areas but sadly no Great Red Spot. I think I am changing my mind about this telescope after all. Moving over to the 18mm (X150) Kasai orthoscopic which seemed to be a bit like looking down the tube from a loo role after the Ethos, I was a little shocked that the view was not quite as good. I was expecting the orthoscopic to just put the icing on the cake but is didn’t on this occasion, that is not to say it will not another day. The Kasai view was very good indeed but not quite so easy on the eye as the 17mm Televue, you had to work that bit harder to see the same detail which was there, you just had to tease it out. This was a fine result and shows you do not have to spend a fortune on an eyepiece to have a top quality view, when all is said and done the Ethos is about 500 pounds more expensive than the Kasai 18mm.

Power!

I move up to a 14mm Delos (X192) to help show the dangers of over egging the pudding and Jupiter did not offer any greater detail, in fact it was not as good, both sets of belts either side of the equatorial, clear in the Ethos were more difficult to pick up, but there. The whole disc just looked somewhat washed out compared to the lesser power, it did not have the same contrast. Just to emphasize the point I slipped in a 10mm Ethos (X270) and the detail of anything but the two main belts had gone and even they were rather difficult to see, I am sure any further increase would have just showed me a creamy white blob for a disc. At this point the fog was starting to form and things were getting wet though I had not dewed up as yet, it was time to call it a day.

Hope you like it,

Alan

[John]

I did like it Alan - lovely report 

I did a bit of viewing of the same objects myself last night with my ED120 refractor. Similar results too with E & F Trapezium being "there" intermittently (not always both at the same time though !). You really do have to play about with eyepieces to get the "right" one for the scope / conditions to see these fainter members of the Trapezium.

On Jupiter last night I found the 6mm Ethos and 5mm Pentax XW gave the best views, clearest contrast and nicest colour, even better than the Astro Hutech and Baader GO's in the same focal lengths on this occasion. Sometimes it's the other way around and I'm not entirely sure why !

I guess it shows that you need to compare equipment on lots of occasions before drawing any conclusions on which is "best". Perhaps the reality is that what is best will vary session to session so thats an excuse to own more than one eyepiece design at our most used focal lengths, as if we need such excuses 

Thanks for posting 

[cotterless45]

Best night for ages here. Got up to x302 , but used a handy x240 in an f6 OO Newt. The detail was staggering , caught the GRS at 11.20 with a dark swathe and details to almost web like belts. Usually I'd be using x160, but this was an extra special night. Spent nearly an hour just on Jupiter.

Then moved on for another few hours on the Leo, Coma , CNv and UMa galaxies,

Nick.

[kerrylewis]

Interesting. I was up from 3.30 onwards and found the seeing on planets to be average at best. I set the scope up just before viewing and not earlier because showers were forecast. Perhaps it needed to cool more? But I was out for around two hours with only slight improvement. I was hoping for better after a really good session a couple of days ago.

Also my friend Lovejoy is fading rapidly - so long, it was good to know you!

[John]

Interesting. I was up from 3.30 onwards and found the seeing on planets to be average at best. I set the scope up just before viewing and not earlier because showers were forecast. Perhaps it needed to cool more? But I was out for around two hours with only slight improvement. I was hoping for better after a really good session a couple of days ago.

Also my friend Lovejoy is fading rapidly - so long, it was good to know you!

It was not exceptional here either. Good enough to enjoy but not really push things too high.

[kerrylewis]

Thanks John. Some comfort to know I wasn't the only one! It's strange but every time seeing is not up to scratch I still need convincing that there is nothing wrong with the equipment!

Kerry

[alan potts]

John,

I am starting to understand now why, as I bleieve you told me, some of our American friends have as many as 200 eyepieces, a little OTT but I get the point.

Really strange how we are about 1800 miles apart and sound as if we had simialr results.  I think the whole thing serves as a lesson, if that is the right word, for some of the new members that are maybe just starting and want to push down hard on the gas peddle, you don't always need it.

I did try Sirius as well but low and jumping around like my son on Christmas day, well another day.

Alan.

[John]

Thanks John. Some comfort to know I wasn't the only one! It's strange but every time seeing is not up to scratch I still need convincing that there is nothing wrong with the equipment!

Kerry

I believe it's called Equipment Inadequacy Paranoia Kerry

Funny how quickly we forget that the same stuff did really well on previous occasions !

Alan: I could not split Sirius either last night. I've still not done it with the ED120. The star image was quite tight but some scintillation was always present.

Definitely agree that sometimes (often ?) less is more. 

[kerrylewis]

I believe it's called Equipment Inadequacy Paranoia Kerry

Funny how quickly we forget that the same stuff did really well on previous occasions !

Spot on John! That's it exactly. 

[Moonshane]

I totally agree that E and F are easier to see when the power is lower. this is also the case with Saturn's moons I find, although in that case sometimes you need a bit more power to convince yourself.

[Pig]

Nice report Alan, again

I have not tried looking for E & F in the trapezium but I will the next time I am out.

I didn't even know Sirius was a double / binary, what sort of mag would splitting it require ?

[chiltonstar]

Nice report Alan, again

I have not tried looking for E & F in the trapezium but I will the next time I am out.

I didn't even know Sirius was a double / binary, what sort of mag would splitting it require ?

Can be quite low (eg x75). The trick is to get Sirius as high as possible, and choose a night with perfect seeing. A red filter helps by cutting the blue scattered and refracted light that makes Sirius B (the "Pup") so difficult to spot this near to the North Pole (ie Sirius is low in the sky from the UK).

Chris

[alan potts]

Chris has summed that up nicely for you Shaun, I have done it on about X50 and believe I have seen it lower than that but you can't beat the star being high,as I get it 32 degrees at best.

I will report tomorrow on more Sirius work and some more on Jupiter and the Trapezium with a different scope, it  was a nice still night tonight.

Alan

[John]

Blimey - you chaps must have much better eyes than me

For me 265x seems to be the optimum power for splitting Sirius and I've only managed it thus far with my 12" dob. I've found some eyepieces do it and some don't if they produce too much light scatter around Sirius A. You do need really steady seeing conditions I find. It's not a particularly close pair at around 8 arc seconds currently but the brightness between the A & B stars is huge and therein lies the challenge.

Edit: Here is a chart of the system Shaun, which should help pinpoint where to look for "the Pup":

[alan potts]

John,

Excellent little chart, I bet 2044 will be difficult.

I believe it is little to do with eyes, I believe it is almost totally down to position in my sky compared to yours. I have many times tried Sirius at the same elevation it reaches in Southern England and have never split the pair, even with the LX, which I have only seen it with once, so you have done very well.  I find my smaller scopes much better, for me it is all about conditions and placing, I am sure is we were in Central Africa with it overhead it would be reasonalbe easy with good equipment, it has by all accounts been split with a 60mm refractor, though I bet not from England. I am also fairly sure wet air is no help of which home sweet home has an abundance.

The other thing that also comes into play is I get the chance to try this about 80-100 times through a winter period, sadly the weather in Britain is rarely that good even in Summer. Many years back when I was in Hull I had a 12.5 inch Newtonian and I never cracked Sirius with that.

Alan.

I am sure you will do it again