Capricorn

Weight is a factor, half the time you will not be bothered to lug it outside and use it owing to the weight.

How about 80% of the time you will not lug it outside to use it?

Seen it happen so many times.

A big dob is an expensive ornament if not used.

Aperture is king is one statement, the other is your best scope is the one you use the most.

Use a small aperture and/or an ND filter.

Optically the same scope, you will get some Chromatic Aberration around bright objects.

They are both 102mm dia, one is f/6.47 = focal length 660mm, the other is f/5 = focal length 500mm

So optically they cannot be the same scope.

Use the polar scope to align the mount, and do it carefully and accurately. Any misunderstanding by adding in the Android App will cause problems and the less to go wrong the better. Also are the instructions accurate enough for AP or just visual?

I knew astrophotography was a challenge, that's opne of the reasons I decided to pick it up - but I should really be able to get more than 5 seconds on an HEQ5 without guiding surely!

Yes you should. Pretty decent polar alignment is not good enough, very accurate is. Welcome to the world of AP.

I also suspect that you will have to perform the alignment since that is really how the system was intended to be set up. It probably need the alignment to know exactly the amount of correction to apply, thinking that there will be some scaling to determine from the data from the guider. The guider has an X/Y (Alt/Az) grid of pixels and the mount operates in polar coordinates so something may have to do a conversion from the Alt/Az movement of the guide star on the guider to the polar coordinates on the mount.

I think you are trying to get it done a bit quicker and easier by side stepping or reducing a few of the actions required. There is no shortcut. Even buying a laptop and additional software, the club I go to has lots. It does not reduce the time to set it all up, it increases the accuracy, and in actual fact set up time probably increases.

You should not be looking to decrease the time, you should be looking to increase the accuracy.

I would say that unless you are spending the first 60 minutes getting it set up, polar aligned and aligned for goto then you are rushing it.

Fast or Slow is a photographic term.

There is a number that is defined as:

FN = (Scope Focal Length) / (Scope objective diameter)

Actually think it is strictly the other way but easier like this.

If the number you get is around the 5-6 mark then the scope is termed Fast

If the number is 8 and above then it is termed Slow.

Between 6 and 8 call it what you feel like.

Below 5 it is Very Fast,

The number as said is a carry over from photography, effectively the Faster the scope the less exposure time you need.

The shutter can move faster and get a picture.

To us in astromony it can be more a measure of how "easy" the scope works.

As a fast scope will have greater curvature on a lens this will cause more problems, Chromatic Aberration and Spherical Aberation being the main.

On a Reflector ther is more Coma and as the secondary can move the alignment (Collimation) is more critical.

Basically a Fast scope is more difficult to produce and can show more errors.

An F/5 achromat will show a fair degree of CA, an achromat of f/10 will show very little.

Fast scope tend to need better eyepieces the slow scopes.

If we are to cast blame on the unrealistic images they see then we also have to consider the unrealistic aspect we here attribute to various scopes and what they can do.

I see many people start here, ask advice, usually get talked out of what they originally intended and then never see them on SGL again. I really would like to know what happened with them. Ever had the feeling they are not happy with what they were told and have decided to give up and walk away ?

How many members are there on SGL and how many have less then 10 posts and not been active in the last year?

I assume all those have gone.

Images are a nightmare, if you reply to say you will not be able to image with that type of mount/scope/system then someone pops up with the one half decent image they took in 2 years and says "Of course you can here is the proof!"

That's what the starter wants to hear and off they go.

Expected views in telescopes are unrealistic, people expect colours, people even expect to see colours in what are x-ray objects, UV objects and IR objects. Utterly ignoring the fact we cannot actually see in those wavelengths at all.

The posts that start out saying I want to look at planets in detail, at DSO's in clarity and produce images to shame Hubble on a maximum budget of £250 are beyond count. Yet we try to break it to them that this will be difficult, without actually saying it specifically. The reality is they might do 1 OR 2 reasonably but 3 is out of the question.

Can you book for the Astrofair via a phone numbr or does it have to be by post?

Just getting a bit late now and it might save a few days, especially as it wil probably take me a couple more days to actually get round to it all.

Had a similar message on an ETX 70, just after I had converted it to run from a mains adaptor and hoped that I could reattach the battery pack as an emergency use thing. No batteries just the plastic holder.

I put the original battery pack (no batteries) back on and the message appeared when the mains adaptor was powering the system, so I disconnected the battery pack and it was fine. Would seem that now I have converted it I cannot reconnect the plastic holder. No great problem.

I therefore have the idea that something goes wrong with the sensing side of it all and there could well not be a problem.

Basically any 1.25" eyepiece will work with your scope.

Skywatcher, Celestron, Meades, BST, GSO, TMB, TV, ES, Vixen, Orion, WO etc, etc.

Entering the LAT and LONG - These coordinates have to be correct.

A little obvious really. No point entering the Lat and Long of Brisbane if you are Birmingham.

Rechargeables are no good because they are 1.2 volts not 1.5 volts, using rechargeables means you are not supplying the required voltage.

Get the right timezone. +00.00 for the UK

This is stated in the handbook, they draw a picture of the time zones and supply the relevant number at the top. This is covered in the handbook.

it assumes a 360 degree clear view.

They all do, the scope has no idea of where you live and the buildings, or whatever, are around you and limit your view.

It also does not know what scope you are using. So some of the DSO's it is listing may be well beyond the resolving power of your scope - The 130p is great but some targets are beyond its power.

If you ask it to goto some object the mount does as requested. Also stand in the middle of dartmoor and that too dim object from your garden may well be visible.

In addition I have had to learn the night sky so as to be able to locate various stars for alignment.

Meade's choose the stars for you, you do not need to know them, just stick in the centre the bright one.

But I have only been able to get up and running quickly by being very prepared in terms of having the right coordinates before I go anywhere with the scope and being very careful when entering data into the handset.

2 options, enter the data while at home before you go anywhere. If it is lost at power off then no good. Meades allow you to enter 6 custom positions so you can preset and just select the new position from the custom list. Alternatively just enter the place you are going to and when powered back on the default is the last location entered.

The Meade's I have all have 4 custom locations entered, I just select the relevant when at the place or, easier, power on at home, select the new location, power off and when I switch it back on this last location is the one used. Level, enter time, DST and tell it to align, literally that is it. As the Lat, long, timezone etc is the one it already has.

Probably good for what you describe as long as you appreciate that there will be some CA of bright objects.

The scope will be easy to use owing to the field of view that it has and the magnification will not be too high. I would guess that a 5mm eyepiece is the magximum mag that is sensible. Basically use the scope for low to medium power observing only.

Shropshire Astronomical Society

Shropshire Astronomical Society - Home Page

Is the only one listed.

Any particular part of Shropshire, just wondering if you live close to a county boarder and there is on in the next county that is close enough.

Since a Dobsonian is a Newtonian asking 6" or 8" is somewhat redundant. Especially as the poll misses out SCT/Mak.

So we have a poll with 2 scopes of the same type, 6" Newtonian or 8" Newtonian, and does not including a type that many astronomers own and use.

8x42's mainly.

Have 15x50's but planets bounce round too much.

Check everything at lest twice over.

One person on SGL was in the same position as you and said the same. EVERYTHING IS ENTERED CORRECT!!!

A visit from someone passing near to them 3 weeks later and after much swapping of ideas solved the problem in 5 minutes. They had entered Lat-Long not Long-Lat.

The scope thought it was close to the equator somewhere around the Bahamas, not Newcastle.

There was a venue, and there was a meal. Pretty good meal.

But it was a few months ago.

For a HEQ5 I use a trolly bag, the long ones with the cloth finish. Not sure what to call them, duffle bag perhaps? They are long enough and the wheels help a lot.

Have used thin ply to form a case/frame/backing and added foam to that. The thing has straps inside so they are used to tie it down.

Problem with a solid case is that the things are heavy to start with and a case simply adds to it all. If just handles then more difficult to move round.

If you want a hard case then I suspect you may have to make one.

I think for Orion the smallest scope I have read reference to that made out colour was a 16 inch.

Orion is, by comparison, very bright. The orion nebula is easily seen by eye, however try the same with Andromeda. After that they get worse.

As to filters, they are called filters because they filter out light:eek: they do not add. Look at it this way sunglasses are neutral density filters.:D

As said magnification makes what you are looking at dimmer. Scope collects the same amount of light and magnification makes the final image bigger. So it is dimmer.

So for the possibility of colour then magnification is the last thing you want, low magnification will collect the gathered light into a smaller final image and so a smaller but brighter image.