John

Great report Baz

It was very nice out last night but a bit nippy I agree.

I observed them last night with my 12 inch dobsonian:

Difficult to say without knowing the scale of your image, it's orientation and the relative brightness of the objects imaged whether you have captured Titania and Oberon or not. They are both around magnitude 14 and were approx 30 and 34 arc seconds from Uranus when I observed them. This is from Stellarium at the time that I observed (newtonian view):

Not sure about the tracking issues but the fall of the optical tube could well have affected the collimation of the optics in the scope even though it fell onto grass.

Contrast of planetary views can go down hill quite fast with SCT's if the collimation is out.

Good to hear that the Vixen 102 achro can still cut it

I used to have one on an SP mount and was very proud of it.

I must give my Vixen ED102SS a spin out soon. It tends to get a little neglected at times

There is always "something better" out there, although generally the margins between quality eyepieces are pretty close. Unless you have Zeiss ZAO's and / or a Pentax XO which I think are the very, very best and have been for some time now.

I've tried to give up chasing now and I'm sticking to the Nagler 2-4 zoom, my Pentax XW's and an HD ortho 4mm. I'll just have to do the best that I can with those

It's interesting and helpful to hear that Takahashi have produced a really nice planetary eyepiece in the TOE's though

11 minutes ago, harry_tarrant said:

Thank you! Do I need any lens filters at all? 

Not really. Just use the lower power eyepieces (20mm and 12.5mm) as you get used to using the scope. The 4mm will make things much more challenging because it gives very high magnifications - it might be useful to view the moon with though.

If you see a circle, the scope is not focused properly. Try using the 12.5mm eyepiece and adjust the focus until Mars appears at it's smallest in the view. It should then look like a very small pinkish spot.

Following my success in spotting Neptune's brightest moon Triton earlier this evening, after a good session observing Mars, I turned my 12 inch dobsonian towards Uranus.

The seeing is steady tonight and Uranus was showing a well defined disk at 398x magnification. Careful observing of the area surrounding the planet showed a faint suspect to the North of the planet with direct vision and another a touch fainter to the West which needed a little averted vision to confirm.

I made a quick sketch of the relative positions of these dim objects and consulted Cartes du Ciel and Stellarium. I was pleased to see both applications showing the two brightest Uranian moons, Titania (magnitude 13.9) and Oberon (magnitude 14.1) in just the positions that I had noted my suspects to be in. I might also have glimpsed Ariel (magnitude 14.3) but that is closer to Uranus as well as fainter and I was not convinced of that one. Titania is currently around 30 arc seconds North of Uranus and Oberon around 34 arc seconds West of it.

I was very pleased to find these two distant moons as I had earlier not been able to see Phobos or Deimos at Mars. I think these Martian moons are somewhat more challenging because they are close in to their much larger (apparent diameter) and brighter parent planet.

While I have seen Triton at Neptune a number of times now, this is just the second occasion that I've been able to see these companion worlds of Uranus

Nice report

I have heard that the TOE's are something special and you seem to confirm that Mark.

Must be very close to the "top tier" of planetary performers.

4 minutes ago, Spacecake2 said:

Actually, I can see four planets Jupiter, Saturn, Neptune and Mars. 

Uranus is not that far from Mars in the sky so that could be a fifth

Triton spotted again this evening with my 12 inch dob at 318x (Pentax 5mm XW).

The magnitude 13.5 moon is 14 arc seconds North of Neptune tonight. This is the newtonian view:

I've owned a couple of TAL 100's and at no time felt the need to filter the small amount of CA that they produced.

2 minutes ago, Ken82 said:

F5 bresser. I did notice quite a bit of coma using my Celestron luminous 31, 23 and baader zoom. I’m not sure if that’s down to collimation or quality of the eyepiece ? 

That could be astigmatism from the eyepiece rather than coma from the scope mirror or maybe a mix of both.

The Ethos are really well corrected in fast scopes - it's what Tele Vue do excellently. Personally I would try the Ethos 21 for a few sessions and see if you see anything towards the field edges that bothers you.

I have the 21, 13, 8 and 6mm Ethos and they are my main set with my 12 inch dob and used without a coma corrector.

This useful article shows what the aberrations look like so you might be able to tell them apart:

http://umich.edu/~lowbrows/reflections/2007/dscobel.27.html

4 hours ago, jetstream said:

This place might have a Sky Watcher dob here in Canada. It might have free shipping to you. They are easy to collimate.

https://focusscientific.com/shipping.php

@John question: is it within the COC for me to post these vendor links? I was never sure.

I'm not a moderator now Gerry but I think it is OK.

A good start down the 100 degree road !

What focal ratio is your dob ?

My 12 inch is F/5.3 but I don't find a CC necessary at that focal ratio with my Ethos's.

Does the scope use foil spacers ?

If so and one of those has moved a bit, that can make an impact on image quality as I've been finding out with a 90mm F/11 achro that I've been playing around with lately.

Lovely scope Jeremy - congratulations

Nice wind-up by Paul as well (I assume)

6 minutes ago, Shepdog said:

I'm keeping an eye on FB marketplace ...not sure of other places within my local area to look..id drive a few hours for a deal for sure..are the dobs difficult to use as long as they are collaminated? And how difficult is it to collaminate? I dont wanns get into something beyond my skill level....yet lol

The "Cloudynights" forum has a classifieds section that is US / Canada based:

https://www.cloudynights.com/classifieds/

The forum is free to join.

Mars opposition this year is a very good one - the best that we will get for many years. I think it's natural that the months leading up to the opposition show an increasing interest in the red planet.

While we do have many members from around the world I guess the majority are from the UK and the EU where Jupiter and Saturn have been low and difficult to observe well recently. At other times those two planets feature much more here than Mars does.

Reports from folks who do have good views of Saturn and Jupiter because of their location are always very welcome of course

When you have been a member for a bit longer I think you will see a different pattern to reports in this section as Mars moves away and it's size dwindles rapidly to a small pink disk. You joined us just as Mars was peaking

1 hour ago, johninderby said:

Celestron, Skywatcher and other mass market brands sell scopes ranging from low end “department store” scopes to some very nice quality scopes so the brand doesn't’ automaticly mean they are good. You have tp pick the right scopes from their lines.

Thats true. A Skywatcher Esprit refractor is a very different quality of product to, say one of their standard Evostar refractors.

The Ring Nebula can seem washed out when there is a bright moon in the sky although last night the moon was on the other side of the sky to Lyra. Sometimes there is high, thin cloud that you are otherwise unaware of which dims nebulous targets.

I find using a bit more magnification helps this target to pop out a bit more. 70x - 120x is good. A UHC filter also enhances the contrast of Messier 57 / The Ring.

Many scopes of the brands you list are made by the same manufacturer now so in many ways it doesn't matter !

Orion (USA) branded scopes can be more expensive in the UK than the Skywatcher or Celestron branded versions.

I've owned scopes by all the brands you list and they seemed to be similar in overall quality. Bresser is one brand that I would add to your list. They are popular on this forum.

Currently I own scopes branded Skywatcher, Celestron, Vixen, Takahashi, APM / LZOS and Orion Optics (UK) and I'm very happy with them all

The challenge at the moment, if buying new, is finding what you want in stock. Stocks are getting very lean with the vendors.

48 minutes ago, Hoopla said:

Hi All, I'd just like to say thanks for all those that have commented.  It's a tad confusing when getting started as you'll all probably remember but the advice has been clear and easy to follow.  

It seems like I now understand regards to the usable magnification and how to calculate this given the kit I have.  If I have then I will try again tonight (weather permitting) by placing my scope outside for a couple of hours and using a 10x eyepiece with a 3x barlow as my scope has a focal length of 750mm which if my calculations are correct works out to 225x magnification?

Then on to working out how I can photograph this with the Canon 700D....

Hi,

The numbers on the eyepieces are their focal lengths in mm so it is 10mm rather than 10x. To get the magnification that a certain eyepiece gives you divide the focal length of the telescope (750mm in your case) by the eyepiece focal length so using a 10mm eyepiece gives you 75x in your scope. Using a 2x barlow doubles the effective focal length of the scope so you then get 150x when using the 10mm eyepiece with the 2x barlow lens. If you use a 3x barlow then it's 225x as you have worked out.

Maximum useful magnification depends on lots of factors including the size and optical quality of the primary mirror or objective lens in the scope, the seeing conditions on that occasion (the main factor really) the state of cooling and collimation of the optics in the scope scope and the target being observed.

In reality much of the observing through telescopes is done at low or medium magnifications so using very high magnifications is not really the be all and end all. On the planets and double stars and often the moon, higher magnifications (say 130x - 250x with your scope) are very useful but for galaxies, clusters and nebulae low to medium magnifications (say 30x - 100x with your scope) are often much more effective.

In theory a 150mm aperture scope should have a maximum useful magnification of 300x or so but that assumes that all the many factors involved come together perfectly and that the target object is suitable. This is only very rarely the case which is why the highest useful magnifications are usually quite a bit lower than the theoretical maximum.

Hope that helps a bit

It is a good question though, so I have given another "like"

Good points Adam.

You are right - the LZOS lens is 105mm. APM (and others) claim that the 107mm triplet is of similar quality to LZOS.

They do all look very similar !