Help me understand my new scope.

[Benton1991]

Hi Guys,

So my scope to date is the Skywatcher Heritage 90 Virtuso and i just don't understand enough of it yet to be able to purchase other things i.e eyepieces and extras when needed and not waste my money.

So basically i will list the things i need out and hopefully you may be able to fill the gaps

I know I'm asking for quiet a bit but worth a shot.

• Whats the range of eye piece best to use? I.e 4mm - 30mm
• What the max magnification can the scope allow and what eyepiece will that be?
• You can use battery packs on then, whats the best to use and where from?
• I here a lot on here about, I.e f/5, what does that mean and whats mine?
• I'm guessing you can use a tripod for this scope, whats the best type to get if this is possible?
• Because I'm a little short on cash at this moment in time and I'm due to be made redundant at the end of April, Would getting a Zoom eyepiece be a better option that buy multi 1 mm sizes?

I can't think of much more at the moment but if i can i will add them later, but one other thing is, i can never get my head round the magnification part at all, I've seen comments around saying a certain eyepiece gives you this mag and this one is this, how do you work it out?

Really sorry if not a lot of that makes sense. On night shift with no sleep during day so eyes are prized open with match sticks with a head like a nodding dog, just not functioning.

Thanks in advance

Matt

[rowan46]

your maximun magnification is worked out by 2xmm apparture  so in your case 180x

your eyepiece magnification is worked out by the scope's focal length divided  by the focal length of the eyepiece eg 1250 divided by 30= aproximately 42x

to work out  the maximum powered eyepiece size focal length of scope divided by maximumum power   1250 divided by 180 = aprox 7 so 7mm is the most powerful eyepiece you should use.

to work out other eyepieces it's the same sum that is focal length divided by required magnification

Many people use power packs from maplins do remember to keep these charged however

F numbers refer to focal ratio it's worked out by dividing the focal length  by the apparture in your case that is 1250 divided by 90 = aprox 14 so f14

zooms are a good way to find out which are your favourite lengths  but generally fixed focal lengths  give better views however this all depends on how much you spend

as to the tripod I don't know if there is a way of attaching a tripod to it I thought it was a table top scope if there's a way to do it somebody will be along to tell you I am sure. hth

[ronin]

The scope is a Mak and 1250mm FL, f/13 = Slow.

I would not consider less then an 8mm eyepiece, 156x.

You will I suspect use a 15mm and 12mm most for the higher end, get a 30mm or 32mm for the "wide" views.

Being a Mak you will find that even "wide" views are not overly wide, a 32mm will give about 1 degree.

Looking at it the scope is not intended for a tripod, it is intended to sit on a table of some sort.

Zoom should be OK on the scope but get one that has "long" focal lengths in range. As I say I suggest not below 8mm. I do not know the ranges that are available so will not quote one. If one existed then something like 10mm - 30mm, 15mm-30mm sort of thing

Power, don't try rechargeables they are 1.2v not 1.5v so too low. Easy first option to get used to it is a pack from £1 Land and use them one night. Maybe get 2 packs and just work through the lot.

When familiar I am unsure what to use as power, Maplins do a small deep cycle 12v at about £28, needs (MUST) to be trickle charged but the right size to sit next to the unit on a table.

The other is the more normal power packs, but if they drain they are damaged, and if you run the scope until it slows down the battery will have been damaged. Makes life difficult.

One stupid sounding option is get a normal power pack and a cheap cooking timer. Set up the scope, aim it at a couple of things to check it and then set the timer to 1 hour. When it goes off that is the end of the observing. Means the battery should not get drained. :eek:  Said it was stupid but it would work.

[PorkyB]

I used to have the same scope, on a manual mount.  It is an excellent scope.

The best way I think you can improve it is to get some decent eyepieces.  I used 25mm, 15mm & 8mm Starguiders (also known as BST explorers).  Search for "Starguider" in ebay.  They are aound £49 each.  That gave magnifications of 50x, 83x and 156x.  I wouldn't get a zoom eyepiece as, at the budget end of the market, the quality will not be as good as the fixed ones.

The other thing I would get is a dew shield.  The scope is very prone to dew.  You can make one from two A4 sheets of 2mm craft foam, or any suitable material like a binder cover that you will find in any stationers.

For power, a Maplins jump starter seems to be the most popular choice.

[brantuk]

See here for a full spec of your scope:

http://www.firstlightoptics.com/heritage/skywatcher-heritage-90-virtuoso.html

• Whats the range of eye piece best to use? I.e 4mm - 30mm

I'd suggest a range giving between 8mm to 30mm in 4-6mm jumps (eg 8, 12, 16, 20, 24, 30). The best one to use will be what you choose on the night - conditions can vary so you'll pick different pieces depending on the seeing.

• What the max magnification can the scope allow and what eyepiece will that be?

See spec for "highest practical power"

• You can use battery packs on then, whats the best to use and where from?

A 12V / 17ah power pack will last all night, and then some, so long as it's just powering the scope. I use a Celestron pack but replaced the battery with a 20ah. I've also had a Maplins one for 3-4yrs which still serves well. There's no particular "best" one but if powering more than just a mount look at leisure batteries with more amp hours.

• I here a lot on here about, I.e f/5, what does that mean and whats mine?

Focal ratio (f) = focal length / aperture (or diameter). So if fl=1500mm and aperture=150 (6") then 1500/150 = f10.

Note: an f-10 scope is regarded as "slow" (good for observing planets) and f-5 is regarded as "fast" (good for LE photography) . f-7 is mid range for dual purpose scopes that are useful for both observing and photography.

• I'm guessing you can use a tripod for this scope, whats the best type to get if this is possible?

Your scope has a 3/8th thread for mounting on Prosumer tripods (whatever they are - I'm guessing camera tripods). But a small dob is better on a level table top - more important to get it level with adjustable feet to preserve "goto" accuracy.

• Because I'm a little short on cash at this moment in time and I'm due to be made redundant at the end of April, Would getting a Zoom eyepiece be a better option that buy multi 1 mm sizes?

A zoom is a good idea but they vary in quality. Skywatcher do a budget level one - so do Seben (of which I've heard good reports). I use a Hyperion zoom which is better quality, and you can get Televue and Pentax ones for which you'll need a second mortgage. Zooms are good alternatives to eyepiece sets - which have always failed to impress me - but single stop eyepieces will always have a performance edge.

Hope that helps.

[Benton1991]

Wow very helpful! Thank you very much guys

Sent from my iPad using Tapatalk HD

[happy-kat]

But you can get going with what you have and enjoy it while hunting your replacement job :-)

Even an old cereal box could be made into a dew shield.

Free software stellarium will show you the night sky.

Free news letter from binocullarsky will give you monthly targets.

For best tracking of an object once found relies on your alighnment, but you can just plonk and go.