+seven_legs Posted October 4, 2015 Share Posted October 4, 2015 hi all, i have a st120 which i really like but was just wondering if people thought its worth increasing aperture size to the st150. would there be much of a differences in views. i have a large dob and would never think to buy a new dob just for a inch and bit more aperture. tony Link to comment Share on other sites More sharing options...
Tweedledee Posted October 4, 2015 Share Posted October 4, 2015 (edited) The difference would be small I think. The ST150 would give 1.5x the light grasp of the ST120, which would equate to about one third of a magnitude gain. You'd have to weigh that against having a heavier and longer OTA which might warrant a better mount. Also the longer focal length would mean a norrower maximum FOV. Edited October 4, 2015 by Tweedledee Link to comment Share on other sites More sharing options...
+seven_legs Posted October 4, 2015 Author Share Posted October 4, 2015 thats what i thought, but i see alot of people on forum upgrading refractors apertures by small amounts and lots of money Link to comment Share on other sites More sharing options...
philjay Posted October 5, 2015 Share Posted October 5, 2015 Its worth it if you want to pull in the faint stuff. I had an st120 and could never get the Veil Nebula without filters an St150 gets it unfiltered. The 150 brings out more fainter stuff in nebuka and if your into galaxy bagging then it brings more in your grasp The 150 is surprisingly a much bigger and heavier scope than the 120, its not just 1" on apeture, its a much bigger cell, tube and dew shield so needs a mount that copes with it. I have an f8 150 and thats even bigger Link to comment Share on other sites More sharing options...
+seven_legs Posted October 5, 2015 Author Share Posted October 5, 2015 That's interesting Phil. I have the st120 on a az4 steel tripod mount. Some people say the az4 would be able to handle the st150 using low power. As I normally do, using 2" eyepieces. What you reckon Link to comment Share on other sites More sharing options...
Tweedledee Posted October 5, 2015 Share Posted October 5, 2015 I've had my AZ4 well loaded up with the ST120 an 80mm finder plus heavy eyepieces, and although it is not ideal, it works ok for low power visual. You could give it a try with the ST150 and then upgrade the mount if necessary . Link to comment Share on other sites More sharing options...
+seven_legs Posted October 5, 2015 Author Share Posted October 5, 2015 That's what I was thinking Pete. But I am in not rush, just something I may get early next year or if I see a cheap second hand one Link to comment Share on other sites More sharing options...
Doc Posted October 6, 2015 Share Posted October 6, 2015 The old adage that aperture rules is correct especially for us visual guys. I would say that it comes a close second behind dark skies for seeing pleasure. Link to comment Share on other sites More sharing options...
philjay Posted October 6, 2015 Share Posted October 6, 2015 Never played with an az4 so dont know its capability but on low power and non windy nights I should imagine it would cope. Link to comment Share on other sites More sharing options...
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