Location, scope and begnner issues when observing

[Roger Fairhurst]

Following advice on this forum I bought my new scope – SW 150/750 EQ3 and added Polarscope, Orion 9/50 finder scope with light and an Omegon SWA 20mm eyepice to compliment my existing 6mm, 12,5mm and 24mm eypieces updated from my 1st scope (Bresser 70/700 ref.).

It arrived Friday 14^th June – assembled and first observations of the moon the same night and – WOW!!

Since then sky overcast and - nowt!

Yesterday evening no clouds visible so outside and set-up ready for darkness.

I had already identified Vega and Arkturus some days ago during partly cloudy skies but now wanted to try and look further and see if I could find M13 in the Keystone.

That’s when the (beginners’) problems started!

1. Identification:
   

I could locate Wega and Arkturus easily enough but I was unable to locate/identify the Keystone about 1/3 the distance between the two. I thought I had it in the finder scope but wasn’t certain. Should all 4 stars of the Keystone be visible in the the finder scope (9/50) at the same time? I certainly couldn’t recognize it in the SW with 20mm SWA eyepiece or with my 10x42 bins.

1. As I had expected, I had to wait until past midnight to stand any chance of seeing enough for recognition purposes which meant I was faced with the second problem:
   

My EQ mount was set to 51° inclination (for my location here in Germany) and Wega and Arktirus were now almost directly overhead which meant the primary end of the tube of the SW fouled the north-pointing tripod leg when I tried to follow a line between the two stars. Also despite re-orienting the tube in its mounting rings it was virtually impossible to find a position where I could see into the finder scope without breaking my neck! Am I doing something fundamentally wrong here or is this just a problem inherent in EQ mounts?

I suspect that my location and recognition issues (as a beginner) were compounded by a warm summer evening (still 20°C at midnight) and light pollution – my wife doesn’t know it yet but her solar powered garden lights are about to be beheaded – they were like a flarepath and the night wasn’t even THAT dark – bet I’m not the first to experience the effects of these imposter light sources! I had taken care to set up early so the scope was at ambient temperature and made sure my eyes were accustomed to the dark and I even used a red light for studying my star charts.

Any help would be appreciated.

Roger

[Oddsocks]

Hello Roger,

I think all new astronomers struggle at first with using small conventional finder scopes, how indeed do you relate the view in the finder to the one on the star chart?

First thing that can help is to download the free planetarium simulation software from Stellarium, here is the link: http://stellarium.org

Once you have the software running just enter the dimensions of the finder scope, eyepiece or bins into the field of view tool and you will see framed on the simulated night sky what you should see looking through the telescope or viewfinder.

You will find Windows, Mac and Linux versions at the top of the main welcome page as well as a PDF copy of the instruction manual a little further down.

I gave up using a normal viewfinder very early on and bought a Telrad reflex finder, very inexpensive and simple to use but there are many other similar "Red Dot Finders" on the market that all do a similar job.

My experience of the Telrad made finding where the telescope was pointing a whole lot easier and of course it doesn't matter where the telescope is rotated to the Telrad or RDF can be viewed from the bottom of the tube if necessary.

Some users invest in a right angle viewfinder which saves your neck but I found it is still difficult to recognise what you are looking at if you can't put the view in context.

I recently attended a star party where two guests were using laser pointers on dobsonian's much to the disgust of everybody else (as if there isn't enough light pollution already!).

The 150/750 on the EQ3 should be able to get fairly close to the zenith before striking the tripod legs but you might need to push the telescope tube higher in the rings and add some extra weight to the primary end to bring the telescope back into balance to achieve this, this is as you state an inherent "feature" of the EQ mount.

You will find quite a few visual astronomers using German Mounts switch to the "pillar" support instead of a tripod support for this very reason, but In a few weeks time the sky overhead will have rotated away from the zenith and then you can try again!

Regards,

William.

[swamp thing]

Hi Roger

Learning to interpret what you see through the finder scope is one of the principle points to star hopping.

I found using my finder to hop from one star to the other helped me a lot in the early days. Pick one of the bright constellation first like Ursa Major or Cassiopeia. Practice hopping around the constellations brighter members. Get a feel for the way the scope moves in the eyepiece of your finder. As you do this you'll be learning the principles that will help you, getting a feel for your finders field of view, and the way it moves.

Once confident, you'll find moving onto dimmer less defined constellations easier.

[umadog]

To be honest, unless you practice a lot with a finder you will struggle. I've been at this for years and have never used a finder for this reason. I prefer to use a Telrad and, if needed, star hop with a low power eyepiece.

[cotterless45]

Chuck the finder scope away and get a rdf or Telrad. I never found a thing with a finderscope starting out. Rdf will allow you to search around the target area.

There are loads of downloadable Telrad charts and the Pocket Sky Atlas has Telrad circles in the front cover,

Nick.

[Tinker1947]

Another vote for the Telrad, its money well spent, along with Stellarium which has the Telrad circle built in, it really gets easy finding DSO's after a bit of practice.....

[Moonshane]

in answer to your question 1 you cannot get the keystone of hercules in a standard finder. a standard 9x50 has a field of about 5 degrees and the keystone is about 8 degrees square. my tip for using star maps is to cut a small circle in black card the size of your finder and using this you can detect what should be visible and star hop easily using it. see http://stargazerslou...-in-the-finder/

I personally prefer a telrad too, and a right and correct image (RACI) finder as they show what the map shows. your scope also shows what the (upside down) map shows.

I would never use and equatorial mount for visual, dobsonians are much better in my opinion. others will advise on how to get around the mount issue who use them I am sure. re the lights, I would for the sake of marital harmony, make some little caps to put on them at night when you are observing. for nights when not observing they are very useful

the sky is currently very poor and will improve steadily over the next month or so. you'll see.

[Tinker1947]

The solar lighting, stick a flower pot over each one, when you out there then remove when you pack up.....

[Roger Fairhurst]

First of all many, many thanks for all the advice and suggestions - it really amazes me how many people on SGL are prepared to take the time and effort to help beginners.

However, it will take some time to process the information received and to decide exactly how I will proceed from here.

I'm basically happy with the scope itself but clearly the mount and finder are issues that need to be resolved. Currently I am a bit restricted with the view from my garden which is 10 meters long (in S direction) but ends with a small stream and woodlands. These trees are 10 - 15m high so as you can imagine I'm severely restricted! Having said that I was able to spot Venus and Jupiter on the few days I was able to use my old scope over the past 18 months so all is not lost. I will probably join the local astro society who have there own observatory but this is holiday time and the next meeting (in a pub, not the observatory!) is at the end of the month then come my holidays.

I will certainly consider an rdf or Telrad although I'm a bit choked off at having paid €99 for an upgrade finder I will probably not use very often! Which finder makes most sense, Telrad or rdf? Do you look down them as with a straight finder scope or from the side like with the main scope? Any particular types to recommend?

The mount is a more serious issue, though and I'm not sure how to proceed here. Are there Dob mounts available for a scope of this size? Will have to take my time in cosidering how to proceed. It seems patience really is a virtue in this hobby - not a bad thing! The skies will get better, I'll join the local society and take trips out of town with them and develop things from there.

Once again many thanks everybody.

Kind regards

Roger

[Roger Fairhurst]

I gave up using a normal viewfinder very early on and bought a Telrad reflex finder, very inexpensive and simple to use but there are many other similar "Red Dot Finders" on the market that all do a similar job. My experience of the Telrad made finding where the telescope was pointing a whole lot easier and of course it doesn't matter where the telescope is rotated to the Telrad or RDF can be viewed from the bottom of the tube if necessary. Some users invest in a right angle viewfinder which saves your neck but I found it is still difficult to recognise what you are looking at if you can't put the view in context. I recently attended a star party where two guests were using laser pointers on dobsonian's much to the disgust of everybody else (as if there isn't enough light pollution already!). The 150/750 on the EQ3 should be able to get fairly close to the zenith before striking the tripod legs but you might need to push the telescope tube higher in the rings and add some extra weight to the primary end to bring the telescope back into balance to achieve this, this is as you state an inherent "feature" of the EQ mount. You will find quite a few visual astronomers using German Mounts switch to the "pillar" support instead of a tripod support for this very reason, but In a few weeks time the sky overhead will have rotated away from the zenith and then you can try again! Regards, William.

Thanks for trhis William - it's all a bit confusing at the outset - like with any hobby - the next move would probably be motor drives but not just yet!

Kind regards

Roger

[Scott]

I know it's more expence but I'd look at replacing the straight through finder with a raci finder like http://www.firstlightoptics.com/finders/skywatcher-9x50-right-angled-erecting-finderscope.html

and another vote for the telrad or rdf. use them both together. the telrad to get close and then the raci. ultimately, it's down to you to decide what works best for you. (personally I use goto )