What would you do?

[solo]

Hi guys and gals,

I can't decide whether to buy a Skywatcher Evostar 120 OTA to replace my Helios 4" or keep it and upgrade it and get the crayford focusser and 9x50 finder. If I replace it I'm only going to get another 38% increase in light gathering capacity.Has anyone done this and if so, was it worth it ?

Cheers. John.

[GazOC]

I've been trying to convince myself to sell my ED100 and get a ED120 but despite my best efforts I just don't see the extra 20mm being worth the extra cost/ weight. I suppose how much cash you'd have to put towards the 120mm after you've sold the 4" will be a big factor?

[solo]

Cost isn't an issue really,in fact i'm not even sure I would sell the 4". It was my first 'scope so I suppose, being the sentimental type, it would be a bit of a wrench to part with it. problem is if I bought the bigger 'scope and found it not much of an improvement then i would have wasted money which I could have used to improve the 4". Decisions,decisions !!

[GazOC]

The difference between a 100mm achro and a 120mm achro isn't going to be huge.

[jcm]

I don't think increasing the aperture by 20mm would make a big enough improvement to justify the cost. I have a 130mm APO , when I wanted to buy an SCT I thought about an 8" but finally decided on a 9.25" so as to get a larger improvement in aperture.

John

[John]

I've owned a 120mm SW Evostar OTA for a short while and tried it alongside my Vixen 102ED. TBH I found that the difference in performance, although noticable, was quite modest and the Evostar 120mm is a pretty bulky OTA so I decided to part with it. I reasoned that by the time I'd got the 120 on a decent mount (I use my 102mm on a Vixen Portamount which is not adequate for the larger refractor) and a tripod tall enough that I did not have to lie down to view the zenith region I'd have spent more than the slight additional performance was worth.

I ended up getting a SW 200P dobsonian which complements the 102mm refractor very well and seems to do very nicely on both DSO's and the moon and planets offering significantly more light grasp and resolution than the refractor.

Nothing wrong with the Evostar 120's though - the views were good but it just did not fit into my lineup.

John

[solo]

Hmm. Yes that's another thing to consider - I use the 4" on an EQ3 which just about the limit for this 'scope even though I've beefed up the aluminimum tripod.I've got an EQ5 for my 8" newt when it's not in DOB mode so I couldn't use that. It's beginning to look like the upgrade.

Cheers. John.